[ { "id": "authors:6ktpc-y4q09", "collection": "authors", "collection_id": "6ktpc-y4q09", "cite_using_url": "https://authors.library.caltech.edu/records/6ktpc-y4q09", "type": "book_section", "title": "Caltech Aerial RGB-Thermal Dataset in the Wild", "author": [ { "family_name": "Lee", "given_name": "Connor", "orcid": "0000-0002-5008-4092", "clpid": "Lee-Connor-T" }, { "family_name": "Anderson", "given_name": "Matthew", "orcid": "0000-0001-8884-3448", "clpid": "Anderson-Matthew-J" }, { "family_name": "Raganathan", "given_name": "Nikhil", "clpid": "Raganathan-Nikhil" }, { "family_name": "Zuo", "given_name": "Xingxing", "orcid": "0000-0003-4158-3153", "clpid": "Zuo-Xingxing" }, { "family_name": "Do", "given_name": "Kevin", "clpid": "Do-Kevin" }, { "family_name": "Gkioxari", "given_name": "Georgia", "clpid": "Gkioxari-Georgia" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "

We present the first publicly-available RGB-thermal dataset designed for aerial robotics operating in natural environments. Our dataset captures a variety of terrain across the United States, including rivers, lakes, coastlines, deserts, and forests, and consists of synchronized RGB, thermal, global positioning, and inertial data. We provide semantic segmentation annotations for 10 classes commonly encountered in natural settings in order to drive the development of perception algorithms robust to adverse weather and nighttime conditions. Using this dataset, we propose new and challenging benchmarks for thermal and RGB-thermal (RGB-T) semantic segmentation, RGB-T image translation, and motion tracking. We present extensive results using state-of-the-art methods and highlight the challenges posed by temporal and geographical domain shifts in our data. The dataset and accompanying code is available at https://github.com/aerorobotics/caltech-aerial-rgbt-dataset.

", "doi": "10.1007/978-3-031-73036-8_14", "isbn": "978-3-031-73035-1", "publisher": "Springer", "place_of_publication": "Cham", "publication": "Computer Vision \u2013 ECCV 2024", "publication_date": "2024-11-21", "pages": "236-256" }, { "id": "authors:yf1k6-9nj40", "collection": "authors", "collection_id": "yf1k6-9nj40", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230526-663037000.22", "type": "book_section", "title": "Interstellar Object Accessibility and Mission Design", "book_title": "2023 IEEE Aerospace Conference", "author": [ { "family_name": "Donitz", "given_name": "Benjamin P. S.", "clpid": "Donitz-Benjamin-P-S" }, { "family_name": "Mages", "given_name": "Declan", "orcid": "0000-0002-2783-2144", "clpid": "Mages-Declan" }, { "family_name": "Tsukamoto", "given_name": "Hiroyasu", "orcid": "0000-0002-6337-2667", "clpid": "Tsukamoto-Hiroyasu" }, { "family_name": "Dixon", "given_name": "Peter", "clpid": "Dixon-Peter" }, { "family_name": "Landau", "given_name": "Damon", "clpid": "Landau-Damon" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Bufanda", "given_name": "Erica", "orcid": "0000-0002-0406-8518", "clpid": "Bufanda-Erica" }, { "family_name": "Ingham", "given_name": "Michel", "orcid": "0000-0001-5893-543X", "clpid": "Ingham-Michel-D" }, { "family_name": "Castillo-Rogez", "given_name": "Julie", "orcid": "0000-0003-0400-1038", "clpid": "Castillo-Rogez-Julie-C" } ], "abstract": "Interstellar objects (ISOs) are fascinating and under-explored celestial objects, providing physical laboratories to understand the formation of our solar system and probe the composition and properties of material formed in exoplanetary systems. In this work, we investigate approaches to designing successful flyby missions to ISOs. We have generated trajec-tories to a series of synthetic representative ISOs, simulating a ground campaign to observe the target and resolve its state, and determining the cruise and close approach \u0394 V required for the encounter. We have developed novel deep learning-driven guidance and control algorithms to enable an accurate flyby of an ISO traveling at velocities over 60 km/s. In this paper, we discuss the accessibility of and mission design to ISOs with varying characteristics, including analysis of state covariance estimation over the course of cruise, handoffs from traditional navigation approaches to novel autonomous navigation for fast flyby regimes, and overall recommendations about preparing for the future in situ exploration of these targets.", "doi": "10.1109/aero55745.2023.10115554", "isbn": "978-1-6654-9032-0", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2023-03", "pages": "1-9" }, { "id": "authors:6nkzy-hw644", "collection": "authors", "collection_id": "6nkzy-hw644", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230526-663062000.31", "type": "book_section", "title": "Resilient Multi-Agent Collaborative Spacecraft Inspection", "book_title": "2023 IEEE Aerospace Conference", "author": [ { "family_name": "Choi", "given_name": "Changrak", "orcid": "0000-0001-8869-6839", "clpid": "Choi-Changrak" }, { "family_name": "Nakka", "given_name": "Yashwanth Kumar", "orcid": "0000-0001-7897-3644", "clpid": "Nakka-Yashwanth-K" }, { "family_name": "Rahmani", "given_name": "Amir", "clpid": "Rahmani-Amir" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "Distributed spacecraft systems (DSS) involving SmallSats in low Earth orbit are gaining significant interest both for Earth observation and on-orbit servicing purposes. However, the miniaturized low-cost components of SmallSats are susceptible to faults, making DSS prone to failures that are detrimental to its overall system performance. In this work, we address the problem of providing resiliency to potential failures for a fleet of spacecraft that are performing on-orbit inspection. The proposed methodology guarantees graceful degradation of the inspection performance even against the worst-case failures, through selection and assignment of formation orbits that are resilient to it. We define quantitative metric to measure collaborative inspection performance, taking into consideration both the information gain and control cost, and formulate worst-case failure of \u2113-spacecraft that maximally undermine it. The main algorithm searches through the space of formation orbits, sampling through a set of orbits with evaluation of its inspection performance in the presence of worst-case failures. The algorithms are designed to be computationally efficient and have linear scaling to the number of spacecraft and orbits, making it applicable to real-time planning for spacecraft swarms. The effectiveness of the proposed approach is validated through simulation experiments on a design reference mission involving five CubeSats inspecting a target spacecraft in low Earth orbit.", "doi": "10.1109/aero55745.2023.10115886", "isbn": "9781665490320", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2023-03" }, { "id": "authors:c7qjb-e2d38", "collection": "authors", "collection_id": "c7qjb-e2d38", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230327-902966000.35", "type": "book_section", "title": "Design of a Lunar Architecture for Tree Traversal in Service of Cabled Exploration", "book_title": "AIAA SCITECH 2023 Forum", "author": [ { "family_name": "Coimbra", "given_name": "Kaila", "orcid": "0000-0002-7239-5035", "clpid": "Coimbra-Kaila-M-Y" }, { "family_name": "Junker", "given_name": "Calle", "clpid": "Junker-Calle" }, { "family_name": "Pabarcius", "given_name": "Lucas", "clpid": "Pabarcius-Lucas" }, { "family_name": "Tisdale", "given_name": "Malcolm G.", "clpid": "Tisdale-Malcolm-G" }, { "family_name": "Boggaram", "given_name": "Sravani", "clpid": "Boggaram-Sravani" }, { "family_name": "Daigle", "given_name": "Robert", "clpid": "Daigle-Robert" }, { "family_name": "Ng", "given_name": "Nathan", "clpid": "Ng-Nathan" }, { "family_name": "Singh", "given_name": "Parul", "clpid": "Singh-Parul" }, { "family_name": "Wexler", "given_name": "Tomas", "clpid": "Wexler-Tomas" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "Traditional wheeled locomotion systems struggle to climb slopes greater than 20\u25e6 and are unable to independently return samples from lunar regions of interest such as ISRU-enabling permanently shadowed polar craters. To reliably enable a diverse range of future robotic activities within lunar craters, this paper presents LATTICE, a lightweight, rapidly deploying, long-lived robotic infrastructure. Utilizing a novel, terrain agnostic, cabled locomotion modality, it is well equipped to repeatedly transport existing robotic systems and scientific hardware into and out of lunar craters and provide power for sustained activities within. LATTICE may be scaled indefinitely, providing a framework for unprecedented bulk transportation of volatile-containing regolith collected in permanently shadowed craters across the lunar surface and beyond.", "doi": "10.2514/6.2023-0020", "isbn": "978-1-62410-699-6", "publisher": "American Institute of Aeronautics and Astronautics", "place_of_publication": "Reston, VA", "publication_date": "2023-01", "pages": "Art. No. 2023-0020" }, { "id": "authors:avmyq-gq082", "collection": "authors", "collection_id": "avmyq-gq082", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230208-295172000.2", "type": "book_section", "title": "Bayesian Active Sensing for Fault Estimation with Belief Space Tree Search", "book_title": "AIAA SCITECH 2023 Forum", "author": [ { "family_name": "Ragan", "given_name": "James", "clpid": "Ragan-James-F" }, { "family_name": "Rivi\u00e8re", "given_name": "Benjamin", "orcid": "0000-0003-4189-4090", "clpid": "Rivi\u00e8re-Benjamin" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "Autonomous spacecraft missions must be robust to system component faults such as sensor and actuator failures. An important setting to study fault tolerance is the Bayesian Active Sensing problem, where the system plans control inputs to gain information and estimate system failures quickly and with high confidence. We model the problem as a belief-state planning problem enabling simultaneous estimation of sensor and actuator failures in the presence of noise. Current belief-state tree search planners provide anytime, approximate solutions, but their underlying particle-filter belief update inhibits performance for information-gathering tasks. To address this issue, we propose POMCPMF, a belief-state tree search that uses an exact belief update in the tree search by exploiting the active sensing problem structure to decouple the belief update as a Kalman filter on the physical state and a particle filter on the failure modes. We validate our method on numerical experiments of spacecraft models with unknown sensor and actuator faults to demonstrate (i) the need for an active and planned sensing solution (as opposed to a passive and greedy solution) and (ii) the superior scalability of our method compared to existing active and planned methods. We then demonstrate the applicability of our algorithm to real systems by extending to a non-linear model and deploying our algorithm on a spacecraft simulator robot.", "doi": "10.2514/6.2023-0874", "isbn": "978-1-62410-699-6", "publisher": "American Institute of Aeronautics and Astronautics", "place_of_publication": "Reston, VA", "publication_date": "2023-01", "pages": "Art. No. 2023-0874" }, { "id": "authors:wq90v-k6k38", "collection": "authors", "collection_id": "wq90v-k6k38", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230327-902943000.32", "type": "book_section", "title": "UAS Flight Testing in Support of Research for Academia: Getting Started and Experiences from the Fields", "book_title": "AIAA SCITECH 2023 Forum", "author": [ { "family_name": "Anderson", "given_name": "Matthew", "orcid": "0000-0001-8884-3448", "clpid": "Anderson-Matthew-J" }, { "family_name": "Lehmkueler", "given_name": "Kai", "clpid": "Lehmkueler-Kai" }, { "family_name": "Randle", "given_name": "Jeremy", "orcid": "0000-0003-4145-3252", "clpid": "Randle-Jeremy" }, { "family_name": "Wong", "given_name": "KC", "orcid": "0000-0002-1008-4012", "clpid": "Wong-KC" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "Uninhabited Aerial Vehicles (UAVs) and miniaturized high-performance computing have enabled flight testing to become incredibly accessible, changing the status quo from an expensive, high-knowledge-barrier endeavour to a relatively low-cost exercise that is within the reach of small-scale research institutions and individuals. Due to this ease of entry, flight testing with UAVs is becoming increasingly commonplace as the technology allows cutting-edge research to leave the realm of simulation and enter real-world trials in very short time frames without the restrictions and costs of piloted, full-scale flight. Where traditional flight test engineers required many years of specialized training, budding UAV flight test engineers often start with little-to-no prior personal or in-house experience, and go through the same trail-and-error processes as those before them. This paper aims to document many years of experience flight testing at a university level, both to provide a basic understanding of the process for anyone getting started, and to share ideas with more experienced operators. It covers aspects such as instrumentation, flight controllers, airframes, bridging the sim-to-real gap and methodologies for conducting safe and efficient flight test campaigns.", "doi": "10.2514/6.2023-0100", "isbn": "978-1-62410-699-6", "publisher": "American Institute of Aeronautics and Astronautics", "place_of_publication": "Reston, VA", "publication_date": "2023-01", "pages": "Art. No. 2023-0100" }, { "id": "authors:7bfgm-vta12", "collection": "authors", "collection_id": "7bfgm-vta12", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220210-928477000", "type": "book_section", "title": "Design of a Modular and Orientable Electrodynamic Shield for Lunar Dust Mitigation", "book_title": "AIAA SCITECH 2022 Forum", "author": [ { "family_name": "Tisdale", "given_name": "Malcom", "clpid": "Tisdale-Malcolm" }, { "family_name": "Dul\u00e1", "given_name": "Isabella", "clpid": "Dul\u00e1-Isabella" }, { "family_name": "Pabon Madrid", "given_name": "Luis", "clpid": "Pabon-Madrid-Luis" }, { "family_name": "Verkhovodova", "given_name": "Polina", "clpid": "Verkhovodova-Polina" }, { "family_name": "P\u00e9not", "given_name": "Jules", "clpid": "P\u00e9not-Jules" }, { "family_name": "Coimbra", "given_name": "Kaila", "clpid": "Coimbra-Kaila" }, { "family_name": "Soldner", "given_name": "Leah", "clpid": "Soldner-Leah" }, { "family_name": "Gupta", "given_name": "Tanmay", "clpid": "Gupta-Tanmay" }, { "family_name": "Musuku", "given_name": "Rithvik", "clpid": "Musuku-Rithvik" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "Lunar dust is considered one of the main limiting factors for lunar missions of extended duration and the establishment of a sustainable human presence on the moon. The dust is difficult to shield against and remove as it is extremely abrasive, highly cohesive, small, and may be electrostatically charged. In addition to threatening astronaut health, lunar dust issues have also resulted in incorrect instrument readings, vision and optical system obscuration, performance reduction, altered thermal properties, and equipment failure. To address these issues, this paper introduces the Habitat Orientable and Modular Electrodynamic Shield (HOMES). HOMES is a collection of 0.25 m x 0.25 m and 1.1 kg panels requiring 8 watts of power, embedded with Electrodynamic Dust Shielding (EDS) to mitigate lunar dust in a variety of applications. The modular design of HOMES addresses the gap in scalability of current EDS implementations. The EDS within HOMES is a series of 3-phase wire electrodes that induce a traveling wave-like electric field to locomote dust particles in a fixed direction. The fringing electric field generated by the EDS can keep dust particles off spacesuits and nearby objects. HOMES is a scalable modular system with rotationally symmetric panels that can be tiled to fit the desired use case. The panels are orientable to allow for customizable field directions. Among other applications, HOMES can be used to create dust free and self-cleaning work surfaces, floors, and doormats. This technology advances the state-of-the-art by incorporating EDS in a lightweight, modular design that will allow for flexibility in lunar dust mitigation within the context of the Artemis missions and beyond. The paper is divided into the following sections: problem statement and background, where the lunar dust problem and the current state of EDS technology are introduced; project description, where project requirements and design assumptions are detailed; mechanical design, outlining the EDS enclosure capable of sustaining the extreme lunar environment and an astronaut's weight; electrical design, detailing the layout of electrodes and EDS electronics; verification and validation, plan to bring homes to Technological Readiness Level 6; path to flight, discussing the necessary steps to ready HOMES for the moon. Having been awarded funding through NASA's BIG Idea Challenge, future work will focus on the construction, testing, and experimental results of this novel technology.", "doi": "10.2514/6.2022-2623", "isbn": "978-1-62410-631-6", "publisher": "American Institute of Aeronautics and Astronautics", "place_of_publication": "Reston, VA", "publication_date": "2022-01-03", "pages": "Art. No. 2022-2623" }, { "id": "authors:2c5rw-jn198", "collection": "authors", "collection_id": "2c5rw-jn198", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220210-928467000", "type": "book_section", "title": "Learning-based methods to model small body gravity fields for proximity operations: Safety and Robustness", "book_title": "AIAA SCITECH 2022 Forum", "author": [ { "family_name": "Neamati", "given_name": "Daniel", "orcid": "0000-0002-1555-1433", "clpid": "Neamati-Daniel" }, { "family_name": "Nakka", "given_name": "Yashwanth Kumar K.", "orcid": "0000-0001-7897-3644", "clpid": "Nakka-Yashwanth-Kumar-K" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "Accurate gravity field models are essential for safe proximity operations around small bodies. State-of-the-art techniques use spherical harmonics or high-fidelity polyhedron shape models. Unfortunately, these techniques can become inaccurate near the surface of the small body or have high computational costs, especially for binary or heterogeneous small bodies. New learning-based techniques do not encode a predefined structure and are more versatile. In exchange for versatility, learning-based techniques can be less robust outside the training data domain. In deployment, the spacecraft trajectory is the primary source of dynamics data. Therefore, the training data domain should include spacecraft trajectories to accurately evaluate the learned model's safety and robustness. We have developed a novel method for learning-based gravity models that directly uses the spacecraft's past trajectories. We further introduce a method to evaluate the safety and robustness of learning-based techniques via comparing accuracy within and outside of the training domain. We demonstrate this safety and robustness method for two learning-based frameworks: Gaussian processes and neural networks. Along with the detailed analysis provided, we empirically establish the need for robustness verification of learned gravity models when used for proximity operations.", "doi": "10.2514/6.2022-2271", "isbn": "978-1-62410-631-6", "publisher": "American Institute of Aeronautics and Astronautics", "place_of_publication": "Reston, VA", "publication_date": "2022-01-03", "pages": "Art. No. 2022-2271" }, { "id": "authors:7pahy-q1y75", "collection": "authors", "collection_id": "7pahy-q1y75", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220210-927992000", "type": "book_section", "title": "Experimental Studies of Propeller-Wing Interactions in Transition from Hover to Forward Flight", "book_title": "AIAA SCITECH 2022 Forum", "author": [ { "family_name": "Tang", "given_name": "Ellande", "clpid": "Tang-Ellande" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "The increasing popularity of Vertical Takeoff and Landing (VTOL) Aircraft in recent years combined with the electrification of propulsion has led to a variety of new configurations in aircraft design. The arrangement of propellers relative to the lifting surfaces introduces aerodynamic interactions that have been less studied in literature. This work outlines a test assembly designed specifically to study the effect of various geometries and their interactions. The assembly is composed of multiple independent subsystems which work in tandem to study the aerodynamic interactions in hover and transition flight. The data show that sub-optimal placement of the propeller can have a significant impact on the performance of the wing, even potentially completely negating the wing's lift at low speeds.", "doi": "10.2514/6.2022-0018", "isbn": "978-1-62410-631-6", "publisher": "American Institute of Aeronautics and Astronautics", "place_of_publication": "Reston, VA", "publication_date": "2022-01-03", "pages": "Art. No. 2022-0018" }, { "id": "authors:50z7m-n0b05", "collection": "authors", "collection_id": "50z7m-n0b05", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220210-721904000", "type": "book_section", "title": "Safe Motion Planning with Tubes and Contraction Metrics", "book_title": "2021 60th IEEE Conference on Decision and Control (CDC)", "author": [ { "family_name": "Singh", "given_name": "Sumeet", "clpid": "Singh-Sumeet" }, { "family_name": "Tsukamoto", "given_name": "Hiroyasu", "orcid": "0000-0002-6337-2667", "clpid": "Tsukamoto-Hiroyasu" }, { "family_name": "Lopez", "given_name": "Brett T.", "clpid": "Lopez-Brett-T" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Slotine", "given_name": "Jean-Jacques", "orcid": "0000-0002-7161-7812", "clpid": "Slotine-Jean-Jacques-E" } ], "abstract": "The recent proliferation of model predictive control (MPC) in safety-critical systems has placed additional emphasis on developing algorithms that have strict performance guarantees despite the presence of modeling error or external disturbances. This tutorial summarizes key results of combining contraction theory with MPC to enable provably-safe motion planning for robotic and aerospace systems. After a brief review of control contraction metrics, we summarize the fundamental result that any closed-loop contracting system has an associated invariant tube centered around a desired trajectory. It is then shown how these tubes can be systematically incorporated into the motion planning problem as an additional safety margin for systems with uncertain dynamics. Finally, several future research directions are discussed.", "doi": "10.1109/cdc45484.2021.9682865", "isbn": "978-1-6654-3659-5", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2021-12-14", "pages": "2943-2948" }, { "id": "authors:ve11k-pb847", "collection": "authors", "collection_id": "ve11k-pb847", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220210-721895000", "type": "book_section", "title": "A Theoretical Overview of Neural Contraction Metrics for Learning-based Control with Guaranteed Stability", "book_title": "2021 60th IEEE Conference on Decision and Control (CDC)", "author": [ { "family_name": "Tsukamoto", "given_name": "Hiroyasu", "orcid": "0000-0002-6337-2667", "clpid": "Tsukamoto-Hiroyasu" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Slotine", "given_name": "Jean-Jacques", "orcid": "0000-0002-7161-7812", "clpid": "Slotine-Jean-Jacques-E" }, { "family_name": "Fan", "given_name": "Chuchu", "orcid": "0000-0003-4671-233X", "clpid": "Fan-Chuchu" } ], "abstract": "This paper presents a theoretical overview of a Neural Contraction Metric (NCM): a neural network model of an optimal contraction metric and corresponding differential Lyapunov function, the existence of which is a necessary and sufficient condition for incremental exponential stability of non-autonomous nonlinear system trajectories. Its innovation lies in providing formal robustness guarantees for learning-based control frameworks, utilizing contraction theory as an analytical tool to study the nonlinear stability of learned systems via convex optimization. In particular, we rigorously show in this paper that, by regarding modeling errors of the learning schemes as external disturbances, the NCM control is capable of obtaining an explicit bound on the distance between a time-varying target trajectory and perturbed solution trajectories, which exponentially decreases with time even under the presence of deterministic and stochastic perturbation. These useful features permit simultaneous synthesis of a contraction metric and associated control law by a neural network, thereby enabling real-time computable and probably robust learning-based control for general control-affine nonlinear systems.", "doi": "10.1109/cdc45484.2021.9682859", "isbn": "978-1-6654-3659-5", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2021-12-14", "pages": "2949-2954" }, { "id": "authors:a5d5g-vg404", "collection": "authors", "collection_id": "a5d5g-vg404", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210510-141344204", "type": "book_section", "title": "Learning-based Adaptive Control using Contraction Theory", "book_title": "2021 60th IEEE Conference on Decision and Control (CDC)", "author": [ { "family_name": "Tsukamoto", "given_name": "Hiroyasu", "clpid": "Tsukamoto-Hiroyasu" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Slotine", "given_name": "Jean-Jacques", "orcid": "0000-0002-7161-7812", "clpid": "Slotine-Jean-Jacques-E" } ], "abstract": "Adaptive control is subject to stability and performance issues when a learned model is used to enhance its performance. This paper thus presents a deep learning-based adaptive control framework for nonlinear systems with multiplicatively-separable parametrization, called adaptive Neural Contraction Metric (aNCM). The aNCM approximates real-time optimization for computing a differential Lyapunov function and a corresponding stabilizing adaptive control law by using a Deep Neural Network (DNN). The use of DNNs permits real-time implementation of the control law and broad applicability to a variety of nonlinear systems with parametric and nonparametric uncertainties. We show using contraction theory that the aNCM ensures exponential boundedness of the distance between the target and controlled trajectories in the presence of parametric uncertainties of the model, learning errors caused by aNCM approximation, and external disturbances. Its superiority to the existing robust and adaptive control methods is demonstrated using a cart-pole balancing model.", "doi": "10.1109/CDC45484.2021.9683435", "isbn": "978-1-6654-3659-5", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2021-12-14", "pages": "2533-2538" }, { "id": "authors:4897p-pqx30", "collection": "authors", "collection_id": "4897p-pqx30", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220224-200754768", "type": "book_section", "title": "Meta-Adaptive Nonlinear Control: Theory and Algorithms", "author": [ { "family_name": "Shi", "given_name": "Guanya", "orcid": "0000-0002-9075-3705", "clpid": "Shi-Guanya" }, { "family_name": "Azizzadenesheli", "given_name": "Kamyar", "orcid": "0000-0001-8507-1868", "clpid": "Azizzadenesheli-Kamyar" }, { "family_name": "O'Connell", "given_name": "Michael", "clpid": "O'Connell-Michael" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Yue", "given_name": "Yisong", "orcid": "0000-0001-9127-1989", "clpid": "Yue-Yisong" } ], "abstract": "We present an online multi-task learning approach for adaptive nonlinear control, which we call Online Meta-Adaptive Control (OMAC). The goal is to control a nonlinear system subject to adversarial disturbance and unknown environment-dependent nonlinear dynamics, under the assumption that the environment-dependent dynamics can be well captured with some shared representation. Our approach is motivated by robot control, where a robotic system encounters a sequence of new environmental conditions that it must quickly adapt to. A key emphasis is to integrate online representation learning with established methods from control theory, in order to arrive at a unified framework that yields both control-theoretic and learning-theoretic guarantees. We provide instantiations of our approach under varying conditions, leading to the first non-asymptotic end-to-end convergence guarantee for multi-task nonlinear control. OMAC can also be integrated with deep representation learning. Experiments show that OMAC significantly outperforms conventional adaptive control approaches which do not learn the shared representation, in inverted pendulum and 6-DoF drone control tasks under varying wind conditions.", "doi": "10.48550/arXiv.2106.06098", "publisher": "Neural Information Processing Systems Foundation, Inc.", "publication_date": "2021-12" }, { "id": "authors:dpc41-x5112", "collection": "authors", "collection_id": "dpc41-x5112", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210825-150704832", "type": "book_section", "title": "Neural Stochastic Contraction Metrics for Learning-based Control and Estimation", "book_title": "2021 American Control Conference (ACC)", "author": [ { "family_name": "Tsukamoto", "given_name": "Hiroyasu", "orcid": "0000-0002-6337-2667", "clpid": "Tsukamoto-Hiroyasu" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Slotine", "given_name": "Jean-Jacques E.", "orcid": "0000-0002-7161-7812", "clpid": "Slotine-Jean-Jacques-E" } ], "abstract": "We present Neural Stochastic Contraction Metrics (NSCM), a new design framework for provably-stable learning-based control and estimation for a class of stochastic nonlinear systems. It uses a spectrally-normalized deep neural network to construct a contraction metric and its differential Lyapunov function, sampled via simplified convex optimization in the stochastic setting. Spectral normalization constrains the state-derivatives of the metric to be Lipschitz continuous, thereby ensuring exponential boundedness of the mean squared distance of system trajectories under stochastic disturbances. The trained NSCM model allows autonomous systems to approximate optimal stable control and estimation policies in real-time, and outperforms existing nonlinear control and estimation techniques including the state-dependent Riccati equation, iterative LQR, EKF, and the deterministic NCM, as shown in simulation results.", "doi": "10.23919/acc50511.2021.9482701", "isbn": "978-1-6654-4197-1", "publisher": "IEEE", "publication_date": "2021-05", "pages": "1275-1280" }, { "id": "authors:x5gn0-f6y92", "collection": "authors", "collection_id": "x5gn0-f6y92", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20211007-145642151", "type": "book_section", "title": "Collaborative Pose Estimation of an Unknown Target Using Multiple Spacecraft", "book_title": "2021 IEEE Aerospace Conference", "author": [ { "family_name": "Matsuka", "given_name": "Kai", "orcid": "0000-0003-2116-9756", "clpid": "Matsuka-Kai" }, { "family_name": "Santamaria-Navarro", "given_name": "Angel", "clpid": "Santamaria-Navarro-Angel" }, { "family_name": "Capuano", "given_name": "Vincenzo", "orcid": "0000-0002-6886-5719", "clpid": "Capuano-Vincenzo" }, { "family_name": "Harvard", "given_name": "Alexei", "clpid": "Harvard-Alexei" }, { "family_name": "Rahmani", "given_name": "Amir", "clpid": "Rahmani-Amir" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "A reliable method for estimating the pose of an unknown and uncooperative space target using monocular vision remains an open problem. Vision-based pose determination is challenging due to factors such as harsh lighting conditions, rotational dynamics of the target, and scale ambiguity of the monocular camera. To address these challenges, we propose a novel collaborative pose determination algorithm called Multi-Spacecraft Simultaneous Estimation of Pose and Shape algorithm or M-SEPS. Within M-SEPS, a team of chaser spacecraft, each equipped with a monocular camera, exchange information over a local network to jointly estimate the relative kinematic state of the target and its sparse shape landmarks. In this approach, each spacecraft processes its images and extracts its own set of visual keypoints in parallel. Then, the team uses the local network to jointly estimate the target pose and shape in a distributed fashion by applying the consensus algorithm over the inter-spacecraft communication links. We validate our algorithm using simulations of relative orbits and observations captured by each chaser spacecraft. To the best of the authors' knowledge, this is the first cooperative vision-based algorithm for estimating the pose and shape of a space object by means of an arbitrary number of spacecraft.", "doi": "10.1109/aero50100.2021.9438352", "isbn": "978-1-7281-7436-5", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2021-03", "pages": "1-11" }, { "id": "authors:zqdwv-3c566", "collection": "authors", "collection_id": "zqdwv-3c566", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210112-105611355", "type": "book_section", "title": "Experimental Model of Effects of Large Upstream Obstructions on Drone Scale Propellers", "book_title": "AIAA Scitech 2021 Forum", "author": [ { "family_name": "Tang", "given_name": "Ellande", "clpid": "Tang-Ellande" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "Recent improvements in computer and electrical energy storage technologies among others have made small Unmanned Aerial Vehicles practical and economical across many design spaces. Recently, designs blending fixed wing and multi-copter elements have become popular as commercial products and research platforms. This configuration has a number of understudied aerodynamic interactions particularly between the rotors and other aerodynamic surfaces. Studying these interactions is key to creating effective designs and developing good models for other aspects of the system such as control and performance evaluation. This paper seeks to understand the effect of occluding the upstream of a propeller at varying distances and varying amounts. The experiments are meant to provide useful guidelines on how far one should position lifting rotors from obstructions such as wings or the fuselage or what the associated trade offs might be. The data indicate that, for large obstructions, the combined effect is significant on performance, but is also predictable regardless of propeller size and pitch, reducing to negligible at roughly one-half propelled diameter.", "doi": "10.2514/6.2021-1648", "isbn": "9781624106095", "publisher": "American Institute of Aeronautics and Astronautics", "place_of_publication": "Reston, VA", "publication_date": "2021-01-11", "pages": "Art. No. 2021-1648" }, { "id": "authors:y683v-rpf72", "collection": "authors", "collection_id": "y683v-rpf72", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210112-105611407", "type": "book_section", "title": "Design of the Next-Generation Autonomous Flying Ambulance", "book_title": "AIAA Scitech 2021 Forum", "author": [ { "family_name": "Tang", "given_name": "Ellande", "clpid": "Tang-Ellande" }, { "family_name": "Spieler", "given_name": "Patrick", "clpid": "Spieler-Patrick" }, { "family_name": "Anderson", "given_name": "Matthew", "clpid": "Anderson-Matthew" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "As electric aircraft take to the skies, it is becoming common to speculate on potential niches in which to apply the technology. One promising role for these vehicles is in the medical domain, a role currently filled by helicopters. A Vertical Take-Off and Landing (VTOL) aircraft with autonomous capabilities could avoid obstacles and transport injured patients to receive critical medical care more quickly than land-based options. This paper presents the design of a novel, fully-electric VTOL aircraft designed to satisfy a medical transport mission by carrying a patient and a paramedic a moderate distance. The paper also presents a scale vehicle model that can be used to test the vehicle design and potential autonomy technologies as well as the special design considerations unique to a VTOL with fixed-wing capabilities. The resultant vehicle will represent the state-of-the-art of what is possible with existing hardware while remaining a flexible platform for autonomy research.", "doi": "10.2514/6.2021-1514", "isbn": "9781624106095", "publisher": "American Institute of Aeronautics and Astronautics", "place_of_publication": "Reston, VA", "publication_date": "2021-01-11", "pages": "Art. No. 2021-1514" }, { "id": "authors:ygdnq-ykp98", "collection": "authors", "collection_id": "ygdnq-ykp98", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210112-105611832", "type": "book_section", "title": "Information-Based Guidance and Control Architecture for Multi-Spacecraft On-Orbit Inspection", "book_title": "AIAA Scitech 2021 Forum", "author": [ { "family_name": "Nakka", "given_name": "Yashwanth Kumar K.", "orcid": "0000-0001-7897-3644", "clpid": "Nakka-Yashwanth-Kumar-K" }, { "family_name": "H\u00f6nig", "given_name": "Wolfgang", "orcid": "0000-0002-0773-028X", "clpid": "H\u00f6nig-Wolfgang" }, { "family_name": "Choi", "given_name": "Changrak", "clpid": "Choi-Changrak" }, { "family_name": "Harvard", "given_name": "Alexei", "clpid": "Harvard-Alexei" }, { "family_name": "Rahmani", "given_name": "Amir", "clpid": "Rahmani-Amir" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "We present an architecture for inspection or mapping of a target spacecraft, referred to as chief, in an orbit around Earth using multiple spacecraft, referred to as deputies (or) observers, in stable Passive Relative Orbits (PROs). We use an information gain approach to directly consider the trade-off between gathered data and fuel/energy cost. The four components of our architecture are: 1) information estimation, 2) state estimation, 3) motion planning for relative orbit initialization and reconfiguration, and 4) relative orbit control. The information estimation quantifies the information gain during inspection of a spacecraft, given past and potential future poses of all spacecraft. The estimated information gain is a crucial input to the motion planner, which computes PROs and reconfiguration strategies for each of the observers to maximize the information gain from distributed observations of the target spacecraft. The resulting motion trajectories jointly consider observational coverage of the target spacecraft and fuel/energy cost. For the PRO trajectories, we design a fuel optimal attitude trajectory that minimizes rest-to-rest energy for each observer to inspect the target spacecraft. We validate our architecture in a mission simulation to visually inspect the target spacecraft.", "doi": "10.2514/6.2021-1103", "isbn": "9781624106095", "publisher": "American Institute of Aeronautics and Astronautics", "place_of_publication": "Reston, VA", "publication_date": "2021-01-11", "pages": "Art. No. 2021-1103" }, { "id": "authors:3h8vn-spg81", "collection": "authors", "collection_id": "3h8vn-spg81", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210112-105611577", "type": "book_section", "title": "Development and Deployment of an Autonomous UAV-Borne Gas and Particulate Sample Capture System for Fumarole Sampling", "book_title": "AIAA Scitech 2021 Forum", "author": [ { "family_name": "Anderson", "given_name": "Matthew", "clpid": "Anderson-Matthew" }, { "family_name": "Backus", "given_name": "Spencer B.", "orcid": "0000-0002-6466-053X", "clpid": "Backus-Spencer-B" }, { "family_name": "Hughes", "given_name": "Ery", "clpid": "Hughes-Ery-C" }, { "family_name": "Curtis", "given_name": "Aaron", "orcid": "0000-0002-2942-4347", "clpid": "Curtis-Aaron" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Stolper", "given_name": "Edward", "orcid": "0000-0001-8008-8804", "clpid": "Stolper-E-M" } ], "abstract": "Volcanoes are one of the great forces of the natural world. The gases they release can reveal information about the world below us, from the structure of the planet, to the risk of an imminent eruption. Sampling these gases however is often difficult and extremely dangerous - high temperatures, hazardous gases, steep terrain and remoteness all make collecting samples a challenging endeavour. Unoccupied Aerial Vehicles (UAVs) can help reduce the risks and difficulties of measuring and sampling these gases, enabling studies of volcanic systems that were otherwise inaccessible. This paper presents the first known effort to design, develop and field test a UAV-borne Gas Capture System (UGCS) for volcanic fumarole sampling. This work includes the development of a sampling probe deployment mechanism, sample canister selection, payload-to-UAV interfacing, and a light-weight visual/thermal camera package. Operationally, the intricacies of placing a sample probe into a small fumarole opening are examined, as are the hazards of flying a UAV with a suspended load.", "doi": "10.2514/6.2021-1409", "isbn": "9781624106095", "publisher": "American Institute of Aeronautics and Astronautics", "place_of_publication": "Reston, VA", "publication_date": "2021-01-11", "pages": "Art. No. 2021-1409" }, { "id": "authors:k462b-vce11", "collection": "authors", "collection_id": "k462b-vce11", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20221222-184439362", "type": "book_section", "title": "The Power of Predictions in Online Control", "book_title": "34th Conference on Neural Information Processing Systems (NeurIPS 2020)", "author": [ { "family_name": "Yu", "given_name": "Chenkai", "orcid": "0000-0001-8683-7773", "clpid": "Yu-Chenkai" }, { "family_name": "Shi", "given_name": "Guanya", "orcid": "0000-0002-9075-3705", "clpid": "Shi-Guanya" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Yue", "given_name": "Yisong", "orcid": "0000-0001-9127-1989", "clpid": "Yue-Yisong" }, { "family_name": "Wierman", "given_name": "Adam", "orcid": "0000-0002-5923-0199", "clpid": "Wierman-A" } ], "contributor": [ { "family_name": "Larochelle", "given_name": "Hugo", "clpid": "Larochelle-Hugo" }, { "family_name": "Ranzato", "given_name": "M.", "clpid": "Ranzato-M" }, { "family_name": "Hadsell", "given_name": "R.", "clpid": "Hadsell-R" }, { "family_name": "Balcan", "given_name": "M. F.", "clpid": "Balcan-M-F" }, { "family_name": "Lin", "given_name": "H.", "clpid": "Lin-H" } ], "abstract": "We study the impact of predictions in online Linear Quadratic Regulator control with both stochastic and adversarial disturbances in the dynamics. In both settings, we characterize the optimal policy and derive tight bounds on the minimum cost and dynamic regret. Perhaps surprisingly, our analysis shows that the conventional greedy MPC approach is a near-optimal policy in both stochastic and adversarial settings. Specifically, for length-T problems, MPC requires only O(logT) predictions to reach O(1) dynamic regret, which matches (up to lower-order terms) our lower bound on the required prediction horizon for constant regret.", "isbn": "9781713829546", "publisher": "Neural Information Processing Foundation", "place_of_publication": "La Jolla, CA", "publication_date": "2020-12", "pages": "1-11" }, { "id": "authors:b3cvj-npn92", "collection": "authors", "collection_id": "b3cvj-npn92", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20221222-183256740", "type": "book_section", "title": "Online Optimization with Memory and Competitive Control", "book_title": "34th Conference on Neural Information Processing Systems (NeurIPS 2020)", "author": [ { "family_name": "Shi", "given_name": "Guanya", "orcid": "0000-0002-9075-3705", "clpid": "Shi-Guanya" }, { "family_name": "Lin", "given_name": "Yiheng", "orcid": "0000-0001-6524-2877", "clpid": "Lin-Yiheng" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Yue", "given_name": "Yisong", "orcid": "0000-0001-9127-1989", "clpid": "Yue-Yisong" }, { "family_name": "Wierman", "given_name": "Adam", "orcid": "0000-0002-5923-0199", "clpid": "Wierman-A" } ], "contributor": [ { "family_name": "Larochelle", "given_name": "Hugo", "clpid": "Larochelle-Hugo" }, { "family_name": "Ranzato", "given_name": "M.", "clpid": "Ranzato-M" }, { "family_name": "Hadsell", "given_name": "R.", "clpid": "Hadsell-R" }, { "family_name": "Balcan", "given_name": "M. F.", "clpid": "Balcan-M-F" }, { "family_name": "Lin", "given_name": "H.", "clpid": "Lin-H" } ], "abstract": "This paper presents competitive algorithms for a novel class of online optimization problems with memory. We consider a setting where the learner seeks to minimize the sum of a hitting cost and a switching cost that depends on the previous p decisions. This setting generalizes Smoothed Online Convex Optimization. The proposed approach, Optimistic Regularized Online Balanced Descent, achieves a constant, dimension-free competitive ratio. Further, we show a connection between online optimization with memory and online control with adversarial disturbances. This connection, in turn, leads to a new constant-competitive policy for a rich class of online control problems.", "isbn": "9781713829546", "publisher": "Neural Information Processing Foundation", "place_of_publication": "La Jolla, CA", "publication_date": "2020-12", "pages": "1-12" }, { "id": "authors:gce3p-skv36", "collection": "authors", "collection_id": "gce3p-skv36", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200805-121745448", "type": "book_section", "title": "Fast Uncertainty Estimation for Deep Learning Based Optical Flow", "book_title": "2020 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)", "author": [ { "family_name": "Lee", "given_name": "Serin", "clpid": "Lee-Serin" }, { "family_name": "Capuano", "given_name": "Vincenzo", "orcid": "0000-0002-6886-5719", "clpid": "Capuano-Vincenzo" }, { "family_name": "Harvard", "given_name": "Alexei", "clpid": "Harvard-Alexei" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "We present a novel approach to reduce the processing time required to derive the estimation uncertainty map in deep learning-based optical flow determination methods. Without uncertainty aware reasoning, the optical flow model, especially when it is used for mission critical fields such as robotics and aerospace, can cause catastrophic failures. Although several approaches such as the ones based on Bayesian neural networks have been proposed to handle this issue, they are computationally expensive. Thus, to speed up the processing time, our approach applies a generative model, which is trained by input images and an uncertainty map derived through a Bayesian approach. By using synthetically generated images of spacecraft, we demonstrate that the trained generative model can produce the uncertainty map 100\u223c700 times faster than the conventional uncertainty estimation method used for training the generative model itself. We also show that the quality of uncertainty map derived by the generative model is close to that of the original uncertainty map. By applying the proposed approach, the deep learning model operated in real-time can avoid disastrous failures by considering the uncertainty as well as achieving better performance removing uncertain portions of the prediction result.", "doi": "10.1109/IROS45743.2020.9340963", "isbn": "978-1-7281-6212-6", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2020-10", "pages": "10138-10144" }, { "id": "authors:pqc5a-vn245", "collection": "authors", "collection_id": "pqc5a-vn245", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200526-151816924", "type": "book_section", "title": "Adaptive Nonlinear Control of Fixed-Wing VTOL with Airflow Vector Sensing", "book_title": "2020 IEEE International Conference on Robotics and Automation (ICRA)", "author": [ { "family_name": "Shi", "given_name": "Xichen", "clpid": "Shi-Xichen" }, { "family_name": "Spieler", "given_name": "Patrick", "clpid": "Spieler-P" }, { "family_name": "Tang", "given_name": "Ellande", "clpid": "Tang-Ellande" }, { "family_name": "Lupu", "given_name": "Elena-Sorina", "orcid": "0000-0002-3968-2630", "clpid": "Lupu-E-S" }, { "family_name": "Tokumaru", "given_name": "Phillip", "clpid": "Tokumaru-Phillip" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "Fixed-wing vertical take-off and landing (VTOL) aircraft pose a unique control challenge that stems from complex aerodynamic interactions between wings and rotors. Thus, accurate estimation of external forces is indispensable for achieving high performance flight. In this paper, we present a composite adaptive nonlinear tracking controller for a fixed- wing VTOL. The method employs online adaptation of linear force models, and generates accurate estimation for wing and rotor forces in real-time based on information from a three-dimensional airflow sensor. The controller is implemented on a custom-built fixed-wing VTOL, which shows improved velocity tracking and force prediction during the transition stage from hover to forward flight, compared to baseline flight controllers.", "doi": "10.1109/ICRA40945.2020.9197344", "isbn": "978-1-7281-7395-5", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2020-08", "pages": "5321-5327" }, { "id": "authors:fxatb-4nw10", "collection": "authors", "collection_id": "fxatb-4nw10", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20191029-155055963", "type": "book_section", "title": "Neural-Swarm: Decentralized Close-Proximity Multirotor Control Using Learned Interactions", "book_title": "2020 IEEE International Conference on Robotics and Automation (ICRA)", "author": [ { "family_name": "Shi", "given_name": "Guanya", "clpid": "Shi-Guanya" }, { "family_name": "H\u00f6nig", "given_name": "Wolfgang", "clpid": "H\u00f6nig-W" }, { "family_name": "Yue", "given_name": "Yisong", "orcid": "0000-0001-9127-1989", "clpid": "Yue-Yisong" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "In this paper, we present Neural-Swarm, a nonlinear decentralized stable controller for close-proximity flight of multirotor swarms. Close-proximity control is challenging due to the complex aerodynamic interaction effects between multirotors, such as downwash from higher vehicles to lower ones. Conventional methods often fail to properly capture these interaction effects, resulting in controllers that must maintain large safety distances between vehicles, and thus are not capable of close-proximity flight. Our approach combines a nominal dynamics model with a regularized permutation-invariant Deep Neural Network (DNN) that accurately learns the high-order multi-vehicle interactions. We design a stable nonlinear tracking controller using the learned model. Experimental results demonstrate that the proposed controller significantly outperforms a baseline nonlinear tracking controller with up to four times smaller worst-case height tracking errors. We also empirically demonstrate the ability of our learned model to generalize to larger swarm sizes.", "doi": "10.1109/ICRA40945.2020.9196800", "isbn": "978-1-7281-7395-5", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2020-08", "pages": "3241-3247" }, { "id": "authors:dg77g-4pr92", "collection": "authors", "collection_id": "dg77g-4pr92", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200831-132647262", "type": "book_section", "title": "Coordinated Motion Planning for On-Orbit Satellite Inspection using a Swarm of Small-Spacecraft", "book_title": "2020 IEEE Aerospace Conference", "author": [ { "family_name": "Bernhard", "given_name": "Benjamin", "clpid": "Bernhard-B" }, { "family_name": "Choi", "given_name": "Changrak", "clpid": "Choi-Changrak" }, { "family_name": "Rahmani", "given_name": "Amir", "clpid": "Rahmani-A" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Hadaegh", "given_name": "Fred", "clpid": "Hadaegh-F-Y" } ], "abstract": "This paper addresses the problem of how to plan optimal motion for a swarm of on-orbit servicing (OOS) small-spacecraft remotely inspecting a non-cooperative client spacecraft in Earth orbit. With the goal being to maximize the information gathered from the coordinated inspection, we present an integrated motion planning methodology that is a) fuel-efficient to ensure extended operation time and b) computationally-tractable to make possible on-board re-planning for improved exploration. Our method is decoupled into first offline selection of optimal orbits, followed by online coordinated attitude planning. In the orbit selection stage, we numerically evaluate the upper and lower bounds of the information gain for a discretized set of passive relative orbits (PRO). The algorithm then sequentially assigns orbits to each spacecraft using greedy heuristics. For the attitude planning stage, we propose a dynamic programming (DP) based attitude planner capable of addressing vehicle and sensor constraints such as attitude control system specifications, sensor field of view, sensing duration, and sensing angle. Finally, we validate the performance of the proposed algorithms through simulation of a design reference mission involving 3U CubeSats inspecting a satellite in low Earth orbit.", "doi": "10.1109/aero47225.2020.9172747", "isbn": "9781728127347", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2020-03", "pages": "1-13" }, { "id": "authors:jtmyz-fcp89", "collection": "authors", "collection_id": "jtmyz-fcp89", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200113-085148391", "type": "book_section", "title": "Approximate Model for Cycle-Averaged Aerodynamic Forces, and its Application to Stability and Control of Bird-Scale Flapping-Wing Aircraft", "book_title": "AIAA Scitech 2020 Forum", "author": [ { "family_name": "Paranjape", "given_name": "Aditya A.", "orcid": "0000-0002-3164-3215", "clpid": "Paranjape-A-A" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Hilton", "given_name": "Harry H.", "clpid": "Hilton-H-H" } ], "abstract": "We derive approximate, closed-form expressions for the cycle-averaged forces produced by flapping wings operating in a regime similar to birds and small unmanned aerial vehicles. The model is 2-D and intended mainly as an aid to performance and stability analysis, and control design. The model accounts for the nonlinear behavior of lift at high angles of attack, corrections for unsteadiness, as well as an elementary expression for drag. As an elementary application of the model, we determine the conditions under which the power consumption is minimized and those under which the range is maximized. We demonstrate how the model can be employed gainfully for stability analysis and control design.", "doi": "10.2514/6.2020-1963", "isbn": "978-1-62410-595-1", "publisher": "American Institute of Aeronautics and Astronautics", "place_of_publication": "Reston, VA", "publication_date": "2020-01-05", "pages": "Art. No. 2020-1963" }, { "id": "authors:55594-4rr29", "collection": "authors", "collection_id": "55594-4rr29", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200113-084156386", "type": "book_section", "title": "Pose Estimation of Uncooperative Spacecraft from Monocular Images Using Neural Network Based Keypoints", "book_title": "AIAA Scitech 2020 Forum", "author": [ { "family_name": "Harvard", "given_name": "Alexei", "clpid": "Harvard-A" }, { "family_name": "Capuano", "given_name": "Vincenzo", "orcid": "0000-0002-6886-5719", "clpid": "Capuano-V" }, { "family_name": "Shao", "given_name": "Eugene Y.", "clpid": "Shao-Eugene-Y" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "A novel method for monocular-based pose estimation of uncooperative spacecraft using keypoints specialized for a given target is presented. A set of robust keypoints are created by examining the effectiveness of existing localization algorithms by simulating and testing different perspectives. The feature extraction and matching is used to build a model of the spacecraft before the flight mission using the same feature extraction algorithms that can be used during the mission. Further, a visibility map is determined for each keypoint to aid in outlier filtering, matching, and measurement covariance estimation. For initialization and matching, a Convolutional Neural Network (CNN) is trained to generate descriptors robust to illumination, scale, and affine changes for the pre-computed keypoints. In the second part of the paper, we focus on pose determination and filtering after keypoint-to-model matching. While several approaches for pose acquisition have been formulated, we propose a novel method for tracking that makes use of a nonlinear filter, based on the spacecraft translational and rotational relative dynamics which estimates the covariance of the vision-based observations using the keypoint preprocessing information. Further, the estimated propagated covariance for each extracted feature is used for aiding the feature matching.", "doi": "10.2514/6.2020-1874", "isbn": "978-1-62410-595-1", "publisher": "American Institute of Aeronautics and Astronautics", "place_of_publication": "Reston, VA", "publication_date": "2020-01-05", "pages": "Art. No. 2020-1874" }, { "id": "authors:wcpyf-xgq44", "collection": "authors", "collection_id": "wcpyf-xgq44", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190918-132428278", "type": "book_section", "title": "Convex Optimization-based Controller Design for Stochastic Nonlinear Systems using Contraction Analysis", "author": [ { "family_name": "Tsukamoto", "given_name": "Hiroyasu", "clpid": "Tsukamoto-Hiroyasu" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "This paper presents an optimal feedback tracking controller for a class of It\u00f4 stochastic nonlinear systems, the design of which involves recasting a nonlinear system equation into a convex combination of multiple non-unique State-Dependent Coefficient (SDC) models. Its feedback gain and controller parameters are found by solving a convex optimization problem to minimize an upper bound of the steady-state tracking error. Multiple SDC parametrizations are utilized to provide a design flexibility to mitigate the effects of stochastic noise and to ensure that the system is controllable. Incremental stability of this controller is studied using stochastic contraction analysis and it is proven that the controlled trajectory exponentially converges to the desired trajectory with a non-vanishing error due to the linear matrix inequality state-dependent algebraic Riccati equation constraint. A discrete-time version of stochastic contraction analysis with respect to a state- and time-dependent metric is also presented in this paper. A simulation is performed to show the superiority of the proposed optimal feedback controller compared to a known exponentially-stabilizing nonlinear controller and a PID controller.", "doi": "10.1109/CDC40024.2019.9028942", "publisher": "IEEE", "publication_date": "2019-12" }, { "id": "authors:z9dpa-x7a96", "collection": "authors", "collection_id": "z9dpa-x7a96", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190918-132943526", "type": "book_section", "title": "Trajectory Optimization for Chance-Constrained Nonlinear Stochastic Systems", "book_title": "2019 IEEE Conference on Decision and Control (CDC)", "author": [ { "family_name": "Nakka", "given_name": "Yashwanth Kumar", "orcid": "0000-0001-7897-3644", "clpid": "Nakka-Yashwanth-K" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "This paper presents a new method of computing a sub-optimal solution of a continuous-time continuous-space chance-constrained stochastic nonlinear optimal control problem (SNOC) problem. The proposed method involves two steps. The first step is to derive a deterministic nonlinear optimal control problem (DNOC) with convex constraints that are surrogate to the SNOC by using generalized polynomial chaos (gPC) expansion and tools taken from chance-constrained programming. The second step is to solve the DNOC problem using sequential convex programming (SCP) for trajectory generation. We prove that in the unconstrained case, the optimal value of the DNOC converges to that of SNOC asymptotically and that any feasible solution of the constrained DNOC is a feasible solution of the chance-constrained SNOC because the gPC approximation of the random variables converges to the true distribution. The effectiveness of the gPC-SCP method is demonstrated by computing safe trajectories for a second-order planar robot model with multiplicative stochastic uncertainty entering at the input while avoiding collisions with a specified probability.", "doi": "10.1109/CDC40024.2019.9028893", "isbn": "978-1-7281-1398-2", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2019-12", "pages": "3811-3818" }, { "id": "authors:9es63-xhk04", "collection": "authors", "collection_id": "9es63-xhk04", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190426-090024789", "type": "book_section", "title": "Robust Estimation Framework with Semantic Measurements", "book_title": "2019 American Control Conference (ACC)", "author": [ { "family_name": "Cai", "given_name": "Karena X.", "clpid": "Cai-Karena-X" }, { "family_name": "Harvard", "given_name": "Alexei", "clpid": "Harvard-A" }, { "family_name": "Murray", "given_name": "Richard M.", "orcid": "0000-0002-5785-7481", "clpid": "Murray-R-M" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "Conventional simultaneous localization and mapping (SLAM) algorithms rely on geometric measurements and require loop-closure detections to correct for drift accumulated over a vehicle trajectory. Semantic measurements can add measurement redundancy and provide an alternative form of loop closure. We propose two different estimation algorithms that incorporate semantic measurements provided by vision-based object classifiers. An a priori map of regions where the objects can be detected is assumed. The first estimation framework is posed as a maximum-likelihood problem, where the likelihood function for semantic measurements is derived from the confusion matrices of the object classifiers. The second estimation framework is comprised of two parts: 1) a continuous-state estimation formulation that includes semantic measurements as a form of state constraints and 2) a discrete-state estimation formulation used to compute the certainty of object detection measurements using a Hidden Markov Model (HMM). The advantages of incorporating semantic measurements in these frameworks are demonstrated in numerical simulations. In particular, the proposed estimation algorithms improve upon the robustness and accuracy of conventional SLAM algorithms.", "doi": "10.23919/ACC.2019.8814793", "isbn": "978-1-5386-7926-5", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2019-07", "pages": "3809-3816" }, { "id": "authors:rg4sd-n6h15", "collection": "authors", "collection_id": "rg4sd-n6h15", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190205-100744248", "type": "book_section", "title": "Neural Lander: Stable Drone Landing Control using Learned Dynamics", "book_title": "2019 International Conference on Robotics and Automation (ICRA)", "author": [ { "family_name": "Shi", "given_name": "Guanya", "orcid": "0000-0002-9075-3705", "clpid": "Shi-Guanya" }, { "family_name": "Shi", "given_name": "Xichen", "orcid": "0000-0002-5366-9256", "clpid": "Shi-Xichen" }, { "family_name": "O'Connell", "given_name": "Michael", "clpid": "O'Connell-Michael" }, { "family_name": "Yu", "given_name": "Rose", "orcid": "0000-0002-8491-7937", "clpid": "Yu-Rose" }, { "family_name": "Azizzadenesheli", "given_name": "Kamyar", "orcid": "0000-0001-8507-1868", "clpid": "Azizzadenesheli-Kamyar" }, { "family_name": "Anandkumar", "given_name": "Animashree", "orcid": "0000-0002-6974-6797", "clpid": "Anandkumar-A" }, { "family_name": "Yue", "given_name": "Yisong", "orcid": "0000-0001-9127-1989", "clpid": "Yue-Yisong" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "Precise near-ground trajectory control is difficult for multi-rotor drones, due to the complex aerodynamic effects caused by interactions between multi-rotor airflow and the environment. Conventional control methods often fail to properly account for these complex effects and fall short in accomplishing smooth landing. In this paper, we present a novel deep-learning-based robust nonlinear controller (Neural-Lander) that improves control performance of a quadrotor during landing. Our approach combines a nominal dynamics model with a Deep Neural Network (DNN) that learns high-order interactions. We apply spectral normalization (SN) to constrain the Lipschitz constant of the DNN. Leveraging this Lipschitz property, we design a nonlinear feedback linearization controller using the learned model and prove system stability with disturbance rejection. To the best of our knowledge, this is the first DNN-based nonlinear feedback controller with stability guarantees that can utilize arbitrarily large neural nets. Experimental results demonstrate that the proposed controller significantly outperforms a Baseline Nonlinear Tracking Controller in both landing and cross-table trajectory tracking cases. We also empirically show that the DNN generalizes well to unseen data outside the training domain.", "doi": "10.1109/ICRA.2019.8794351", "isbn": "978-1-5386-6027-0", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2019-05", "pages": "9784-9790" }, { "id": "authors:2xm5m-zcx96", "collection": "authors", "collection_id": "2xm5m-zcx96", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20191205-094833503", "type": "book_section", "title": "Approach to exploring interstellar objects and long-period comets", "book_title": "Spaceflight Mechanics 2019", "author": [ { "family_name": "Castillo-Rogez", "given_name": "Julie C.", "clpid": "Castillo-Rogez-J-C" }, { "family_name": "Meech", "given_name": "Karen", "orcid": "0000-0002-2058-5670", "clpid": "Meech-K-J" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Landau", "given_name": "Damon", "clpid": "Landau-D" } ], "contributor": [ { "family_name": "Topputo", "given_name": "Francesco", "clpid": "Topputo-F" }, { "family_name": "Sinclair", "given_name": "Andrew J.", "clpid": "Sinclair-A-J" }, { "family_name": "Wilkins", "given_name": "Matthew P.", "clpid": "Wilkins-M-P" }, { "family_name": "Zanetti", "given_name": "Renato", "clpid": "Zanetti-R" } ], "abstract": "This paper aims to identify the best approaches for exploring planetary bodies with very long orbital periods, i.e., bodies that approach Earth only once in a lifetime. This includes long-period comets (LPCs), and the newly discovered classes of Manx comets and interstellar objects (ISOs). Long-period comets are high scientific value targets, as indicated in the current Planetary Science Decadal Survey. Interstellar objects open the fascinating possibility to sample exoplanetary systems. Manxes hold the key to resolving long-time questions about the early history of our solar system. Specific strategies need to be implemented in order to approach bodies whose orbital properties are at the same time extreme and unpredictable. As ground-based telescope capabilities are greatly improving, it will soon become possible to detect LPCs more than ten years before they reach perihelion. On the other hand, the non- or weakly active Manx comets and ISOs require reactive exploration strategies. All of these bodies offer many challenges for close proximity observations that can be addressed by the deployment of multi-spacecraft architectures. We describe several concepts that leverage the many advantages offered by distributed sensors, fractionated payload, and various mother-daughter configurations to achieve high impact science within the reach of low-cost missions.", "isbn": "9780877036593", "publisher": "American Astronautical Society", "place_of_publication": "San Diego, CA", "publication_date": "2019-01", "pages": "2115-2128" }, { "id": "authors:xr8xv-19x05", "collection": "authors", "collection_id": "xr8xv-19x05", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180925-090601879", "type": "book_section", "title": "Nonlinear Control of Autonomous Flying Cars with Wings and\n Distributed Electric Propulsion", "book_title": "2018 IEEE Conference on Decision and Control (CDC)", "author": [ { "family_name": "Shi", "given_name": "Xichen", "clpid": "Shi-Xichen" }, { "family_name": "Kim", "given_name": "Kyunam", "orcid": "0000-0002-7803-1582", "clpid": "Kim-Kyunam" }, { "family_name": "Rahili", "given_name": "Salar", "clpid": "Rahili-S" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "Hybrid vertical take-off and landing vehicles (VTOL) with lift production from wings and distributed propulsive system present unique control challenges. Existing methods tend to stitch and switch different controllers specially designed for fixed-wing aircraft or multicopters. In this paper, we present a unified framework for designing controllers for such winged VTOL vehicles that are commonly found in recent flying car models. The proposed method is broken down into nonlinear control of both position and attitude with forces and moments\nas inputs, and real-time control allocation that integrates distributed propulsive actuation with conventional control surface deflection. We also present a strategy that avoids saturation of distributed propulsion control inputs. The effectiveness of the proposed framework is demonstrated through simulation and closed-loop flight experiment with our winged VTOL flying car prototype.", "doi": "10.1109/CDC.2018.8619578", "isbn": "978-1-5386-1395-5", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2018-12", "pages": "5326-5333" }, { "id": "authors:e700a-55z91", "collection": "authors", "collection_id": "e700a-55z91", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20181010-125618747", "type": "book_section", "title": "Optimal Routing for Autonomous Taxis using Distributed Reinforcement Learning", "author": [ { "family_name": "Rahili", "given_name": "Salar", "clpid": "Rahili-S" }, { "family_name": "Riviere", "given_name": "Benjamin", "clpid": "Riviere-B" }, { "family_name": "Oliver", "given_name": "Suzanne", "clpid": "Oliver-Suzanne" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "In this paper, a learning-based optimal transportation\nalgorithm for autonomous taxis and ridesharing vehicles is\nintroduced. The goal is to design a mechanism to solve the routing problem for a fleet of autonomous vehicles in real-time in order to maximize the transportation company's profit. To solve this problem, the system is modeled as a Markov Decision Process (MDP) using past customers data. By solving the defined MDP, a centralized high-level planning recommendation is obtained, where this offline solution is used as an initial value for the real-time learning. Then, a distributed SARSA reinforcement learning algorithm is proposed to capture the model errors and the environment changes, such as variations in customer distributions in each area, traffic, and fares, thereby providing an accurate model and optimal policies in real-time. Agents are using only their local information and interaction, such as current passenger requests and estimates of neighbors' tasks and their optimal actions, to obtain the optimal policies in a distributed fashion. The agents use the estimated values of each action, provided by distributed SARSA reinforcement learning, in a distributed game-theory based task assignment to select their conflict-free customers. Finally, the customers data provided by the city of Chicago is used to validate the proposed algorithms.", "publisher": "IEEE", "publication_date": "2018-10-10" }, { "id": "authors:r1424-xmc64", "collection": "authors", "collection_id": "r1424-xmc64", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180816-145831065", "type": "book_section", "title": "A Six Degree-of-Freedom Spacecraft Dynamics Simulator for Formation Control Research", "author": [ { "family_name": "Nakka", "given_name": "Yashwanth Kumar", "orcid": "0000-0001-7897-3644", "clpid": "Nakka-Yashwanth-K" }, { "family_name": "Foust", "given_name": "Rebecca C.", "orcid": "0000-0003-1470-1716", "clpid": "Foust-Rebecca" }, { "family_name": "Lupu", "given_name": "Elena Sorina", "orcid": "0000-0002-3968-2630", "clpid": "Lupu-E-S" }, { "family_name": "Elliott", "given_name": "David B.", "clpid": "Elliott-D-B" }, { "family_name": "Crowell", "given_name": "Irene S.", "clpid": "Crowell-I-S" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Hadaegh", "given_name": "Fred Y.", "clpid": "Hadaegh-F-Y" } ], "abstract": "This paper presents a new six-degree-of-freedom robotic spacecraft simulator, the Multi-Spacecraft Testbed for Autonomy Research (M-STAR), for testing formation\nguidance, relative navigation, and control algorithms. The simulator dynamics are governed by five degrees of frictionless translational and rotational air-bearing\nmotion and one degree of kinematic motion in the gravity direction with flight-like actuators, in a 1-g environment. M-STAR is designed to be modular and accommodates\n3-DOF, 4-DOF, 5-DOF, and 6-DOF operation with minimal mechanical modifications. The simulator is modelled as a 3-D pendulum on a floating platform with sixteen thrusters and four reaction wheels as on-board actuators. Based\non this plant model, a nonlinear hierarchical control law is proposed for position and attitude trajectory tracking. A weighted generalized pseudo-inverse strategy\nfor control allocation to map control inputs to actuator inputs is discussed. The thruster actuation model for mapping smooth allocated input to non-smooth actuator\ninput that achieves equivalent performance is derived. The control law, allocation scheme, and thruster model are tested on the simulator for real-time position tracking control using a Robot Operating System (ROS) based software\nframework.", "publisher": "AIAA", "publication_date": "2018-08" }, { "id": "authors:x02zq-w8133", "collection": "authors", "collection_id": "x02zq-w8133", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20171214-123928298", "type": "book_section", "title": "Distributed Spatiotemporal Motion Planning for Spacecraft Swarms in Cluttered Environments", "book_title": "AIAA SPACE and Astronautics Forum and Exposition", "author": [ { "family_name": "Bandyopadhyay", "given_name": "Saptarshi", "clpid": "Bandyopadhyay-S" }, { "family_name": "Baldini", "given_name": "Francesca", "clpid": "Baldini-F" }, { "family_name": "Foust", "given_name": "Rebecca", "orcid": "0000-0003-1470-1716", "clpid": "Foust-Rebecca" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Rahmani", "given_name": "Amir", "clpid": "Rahmani-A" }, { "family_name": "de la Croix", "given_name": "Jean-Pierre", "clpid": "de-la-Croix-Jean-Pierre" }, { "family_name": "Hadaegh", "given_name": "Fred Y.", "clpid": "Hadaegh-F-Y" } ], "abstract": "This paper focuses on trajectory planning for spacecraft swarms in cluttered environments, like debris fields or the asteroid belt. Our objective is to reconfigure the spacecraft swarm to a desired formation in a distributed manner while minimizing fuel and avoiding collisions among themselves and with the obstacles. In our prior work we proposed a novel distributed guidance algorithm for spacecraft swarms in static environments. In this paper, we present the Multi-Agent Moving-Obstacles Spherical Expansion and Sequential Convex Programming (MAMO SE-SCP) algorithm that extends our prior work to include spatiotemporal constraints such as time-varying, moving obstacles and desired time-varying terminal positions. In the MAMO SE-SCP algorithm, each agent uses a spherical-expansion-based sampling algorithm to cooperatively explore the time-varying environment, a distributed assignment algorithm to agree on the terminal position for each agent, and a sequential-convex-programming-based optimization step to compute the locally-optimal trajectories from the current location to the assigned time-varying terminal\nposition while avoiding collision with other agent and the moving obstacles. Simulations results demonstrate that the proposed distributed algorithm can be used by a spacecraft\nswarm to achieve a time-varying, desired formation around an object of interest in a dynamic environment with many moving and tumbling obstacles.", "doi": "10.2514/6.2017-5323", "isbn": "978-1-62410-483-1", "publisher": "American Institute of Aeronautics and Astronautics", "publication_date": "2017-09", "pages": "Art. No. 2017-5323" }, { "id": "authors:whzaf-n4734", "collection": "authors", "collection_id": "whzaf-n4734", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170523-114359601", "type": "book_section", "title": "Describing Robotic Bat Flight with Stable Periodic Orbits", "book_title": "Biomimetic and Biohybrid Systems", "author": [ { "family_name": "Ramezani", "given_name": "Alireza", "orcid": "0000-0002-3391-5288", "clpid": "Ramezani-Alireza" }, { "family_name": "Ahmed", "given_name": "Syed Usman", "clpid": "Syed-U-A" }, { "family_name": "Hoff", "given_name": "Jonathan", "clpid": "Hoff-Jonathan" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Hutchinson", "given_name": "Seth", "orcid": "0000-0002-3949-6061", "clpid": "Hutchinson-Seth" } ], "contributor": [ { "family_name": "Mangan", "given_name": "Michael", "clpid": "Mangan-M" }, { "family_name": "Cutosky", "given_name": "Mark", "clpid": "Cutosky-M" }, { "family_name": "Mura", "given_name": "Anna", "clpid": "Mura-A" }, { "family_name": "Verschure", "given_name": "Paul F. M. J.", "clpid": "Verschure-P-F-M-J" }, { "family_name": "Prescott", "given_name": "Tony", "clpid": "Prescott-T" }, { "family_name": "Lepora", "given_name": "Nathan", "clpid": "Lepora-N" } ], "abstract": "From a dynamic system point of view, bat locomotion stands out among other forms of flight. During a large part of bat wingbeat cycle the moving body is not in a static equilibrium. This is in sharp contrast to what we observe in other simpler forms of flight such as insects, which stay at their static equilibrium. Encouraged by biological examinations that have revealed bats exhibit periodic and stable limit cycles, this work demonstrates that one effective approach to stabilize articulated flying robots with bat morphology is locating feasible limit cycles for these robots; then, designing controllers that retain the closed-loop system trajectories within a bounded neighborhood of the designed periodic orbits. This control design paradigm has been evaluated in practice on a recently developed bio-inspired robot called Bat Bot (B2).", "doi": "10.1007/978-3-319-63537-8_33", "isbn": "978-3-319-63536-1", "publisher": "Springer", "place_of_publication": "Cham", "publication_date": "2017-07-16", "pages": "394-405" }, { "id": "authors:ed2ww-4eh93", "collection": "authors", "collection_id": "ed2ww-4eh93", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170523-120929316", "type": "book_section", "title": "Reducing Versatile Bat Wing Conformations to a 1-DoF Machine", "book_title": "Biomimetic and Biohybrid Systems", "author": [ { "family_name": "Hoff", "given_name": "Jonathan", "clpid": "Hoff-Jonathan" }, { "family_name": "Ramezani", "given_name": "Alireza", "orcid": "0000-0002-3391-5288", "clpid": "Ramezani-Alireza" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Hutchinson", "given_name": "Seth", "orcid": "0000-0002-3949-6061", "clpid": "Hutchinson-Seth" } ], "contributor": [ { "family_name": "Mangan", "given_name": "Michael", "clpid": "Mangan-M" }, { "family_name": "Cutkosky", "given_name": "Mark", "clpid": "Cutkosky-M-R" }, { "family_name": "Mura", "given_name": "Anna", "clpid": "Mura-A" }, { "family_name": "Verschure", "given_name": "Paul F. M. J.", "clpid": "Verschure-P-F-M-J" }, { "family_name": "Prescott", "given_name": "Tony", "clpid": "Prescott-T" }, { "family_name": "Lepora", "given_name": "Nathan", "clpid": "Lepora-N" } ], "abstract": "Recent works have shown success in mimicking the flapping flight of bats on the robotic platform Bat Bot (B2). This robot has only five actuators but retains the ability to flap and fold-unfold its wings in flight. However, this bat-like robot has been unable to perform folding-unfolding of its wings within the period of a wingbeat cycle, about 100 ms. The DC motors operating the spindle mechanisms cannot attain this folding speed. Biological bats rely on this periodic folding of their wings during the upstroke of the wingbeat cycle. It reduces the moment of inertia of the wings and limits the negative lift generated during the upstroke. Thus, we consider it important to achieve wing folding during the upstroke. A mechanism was designed to couple the flapping cycle to the folding cycle of the robot. We then use biological data to further optimize the mechanism such that the kinematic synergies of the robot best match those of a biological bat. This ensures that folding is performed at the correct point in the wingbeat cycle.", "doi": "10.1007/978-3-319-63537-8_16", "isbn": "978-3-319-63536-1", "publisher": "Springer", "place_of_publication": "Cham, Switzerland", "publication_date": "2017-07-16", "pages": "181-192" }, { "id": "authors:2jq6j-xh523", "collection": "authors", "collection_id": "2jq6j-xh523", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170630-094657577", "type": "book_section", "title": "Trajectory Design of a Spacecraft Formation for Space-Based Solar Power Using Sequential Convex Programming", "author": [ { "family_name": "Goel", "given_name": "Ashish", "clpid": "Goel-Ashish" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Pellegrino", "given_name": "Sergio", "orcid": "0000-0001-9373-3278", "clpid": "Pellegrino-S" } ], "abstract": "The concept of collecting solar power in space and transmitting it to the Earth using microwaves has been studied by numerous researchers in the past. The Space Solar Power Initiative (SSPI) at Caltech is a collaborative project to bring about the scientific and technological innovations necessary for enabling a space-based solar power system. The proposed system comprises an array of ultra-light, membrane-like deployable modules with high efficiency photovoltaic (PV) concentrators and microwave transmission antennas embedded in the structure. Each module is 60m x 60m in size and in the final configuration, hundreds of these modules span a 3km x 3km array in a geosynchronous orbit. As this formation goes around the Earth, the orientation and position of each module has to be changed so as to optimize the angle made by the photovoltaic surface with respect to the sun and by the antenna surface with respect to the receiving station on Earth. In order to achieve high antenna array efficiency, the modules have to remain in a tight formation with an edge-to-edge distance on the order of a few meters. In addition, the modules also have to avoid collisions and maintain a planar configuration to avoid the possibility of both PV and RF shadowing. In this paper, we present the trajectory design that achieves the dual goal of minimizing the propellant usage and maximizing the power delivered to the ground station, while meeting the various orbital constraints. The optimal control problem is solved using sequential convex programming for a 4 x 4 formation and the results obtained show that it is possible to maintain the formation for 11 years in a geo-synchronous orbit with relatively small amounts of propellant. This serves as a critical achievement in the path towards realizing the objective of space-based solar power.", "publisher": "Caltech Library", "publication_date": "2017-06" }, { "id": "authors:geqnd-t1923", "collection": "authors", "collection_id": "geqnd-t1923", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170523-114956940", "type": "book_section", "title": "From Rousettus aegyptiacus (bat) Landing to Robotic Landing: Regulation of CG-CP Distance Using a Nonlinear Closed-Loop Feedback", "book_title": "2017 IEEE International Conference on Robotics and Automation", "author": [ { "family_name": "Syed", "given_name": "Usman A.", "clpid": "Syed-U-A" }, { "family_name": "Ramezani", "given_name": "Alireza", "orcid": "0000-0002-3391-5288", "clpid": "Ramezani-Alireza" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Hutchinson", "given_name": "Seth", "orcid": "0000-0002-3949-6061", "clpid": "Hutchinson-Seth" } ], "abstract": "Bats are unique in that they can achieve unrivaled agile maneuvers due to their functionally versatile wing conformations. Among these maneuvers, roosting (landing) has captured attentions because bats perform this acrobatic maneuver with a great composure. This work attempts to reconstruct bat landing maneuvers with a Micro Aerial Vehicle (MAV) called Allice. Allice is capable of adjusting the position of its Center of Gravity (CG) with respect to the Center of Pressure (CP) using a nonlinear closed-loop feedback. This nonlinear control law, which is based on the method of input-output feedback linearization, enables attitude regulations through variations in CG-CP distance. To design the model-based nonlinear controller, the Newton-Euler dynamic model of the robot is considered, in which the aerodynamic coefficients of lift and drag are obtained experimentally. The performance of the proposed control architecture is validated by conducting several experiments.", "doi": "10.1109/ICRA.2017.7989408", "isbn": "978-1-5090-4633-1", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2017-06", "pages": "3560-3567" }, { "id": "authors:kt4zj-a7s05", "collection": "authors", "collection_id": "kt4zj-a7s05", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170630-095327924", "type": "book_section", "title": "Distributed Fast Motion Planning for Spacecraft Swarms in Cluttered Environments Using Spherical Expansions and Sequence of Convex Optimization Problems", "author": [ { "family_name": "Bandyopadhyay", "given_name": "Saptarshi", "clpid": "Bandyopadhyay-S" }, { "family_name": "Baldini", "given_name": "Francesca", "clpid": "Baldini-F" }, { "family_name": "Foust", "given_name": "Rebecca", "orcid": "0000-0003-1470-1716", "clpid": "Foust-Rebecca" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Rahmani", "given_name": "Amir", "clpid": "Rahmani-A" }, { "family_name": "de la Croix", "given_name": "Jean-Pierre", "clpid": "de-la-Croix-J-P" }, { "family_name": "Hadaegh", "given_name": "Fred Y.", "clpid": "Hadaegh-F-Y" } ], "abstract": "This paper presents a novel guidance algorithm for spacecraft swarms in an environment cluttered with many obstacles like a debris field or the asteroid belt. The objective of this algorithm is to reconfigure the swarm to a desired formation in a distributed manner while minimizing fuel and avoiding collisions among themselves and with the obstacles. The agents first use a spherical-expansion-based sampling algorithm to cooperatively explore the workspace and find paths to the desired terminal positions. Using a distributed assignment algorithm, the agents converge on an optimal assignment of the target locations in the desired formation. Then each agent generates a locally optimal trajectory from its current location to its terminal position by solving a sequence of convex optimization problems. As the agent moves along this trajectory, it receives the position of other agents and\nupdates its trajectory to avoid collisions with other agents and the obstacles. Thus the swarm achieves the desired formation in a distributed manner while avoiding collisions. Moreover, this algorithm is computationally efficient, therefore it can be implemented onboard resource-constrained spacecraft. Simulations results show that the proposed distributed algorithm can be used by a spacecraft swarm to reconfigure a desired formation around an asteroid in a collision-free manner.", "publisher": "Caltech Library", "publication_date": "2017-06" }, { "id": "authors:gx87d-30m64", "collection": "authors", "collection_id": "gx87d-30m64", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170630-100154807", "type": "book_section", "title": "Automated Rendezvous and Docking Using Tethered Formation Flight", "author": [ { "family_name": "Foust", "given_name": "Rebecca C.", "orcid": "0000-0003-1470-1716", "clpid": "Foust-Rebecca" }, { "family_name": "Nakka", "given_name": "Yashwanth K.", "orcid": "0000-0001-7897-3644", "clpid": "Nakka-Yashwanth-K" }, { "family_name": "Saxena", "given_name": "Ayush", "clpid": "Saxena-Ayush" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Hadaegh", "given_name": "Fred Y.", "clpid": "Hadaegh-F-Y" } ], "abstract": "This paper analyzes capture strategies for tether-based autonomous rendezvous and docking. Once both spacecrafts are connected by tethers, docking is achieved through the use of reaction wheels and tether motors without the use of propellant. Autonomous rendezvous and docking is crucial for many upcoming missions including on-orbit servicing and potential Mars missions. The tether-based capture strategies investigated are a spin-up tether deployment and a free-flying child spacecraft attaching the tether. These strategies are compared to a traditional two-agent propulsive docking strategy. The capture strategies are simulated from initial orbit through to completed dock, with the total fuel consumption and dock time compared, along with initial pointing/location requirements. In addition to having lower fuel cost, the tether-based strategies are also more reliable due to redundancy, since tethers can be reeled back in and multiple tethers can be stored for use in case of primary tether failure.", "publisher": "Caltech Library", "publication_date": "2017-06" }, { "id": "authors:11d17-hk645", "collection": "authors", "collection_id": "11d17-hk645", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170412-170605649", "type": "book_section", "title": "Sub-optimal boundary control of semilinear pdes using a dyadic perturbation observer", "book_title": "IEEE 55th Conference on Decision and Control (CDC)", "author": [ { "family_name": "Paranjape", "given_name": "Aditya A.", "orcid": "0000-0002-3164-3215", "clpid": "Paranjape-A-A" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "In this paper, we present a sub-optimal controller for semilinear partial differential equations, with partially known nonlinearities, in the dyadic perturbation observer (DPO) framework. The dyadic perturbation observer uses a two-stage perturbation observer to isolate the control input from the nonlinearities, and to predict the unknown parameters of the nonlinearities. This allows us to apply well established tools from linear optimal control theory to the controlled stage of the DPO. The small gain theorem is used to derive a condition for the robustness of the closed loop system.", "doi": "10.1109/CDC.2016.7798459", "isbn": "978-1-5090-1837-6", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2016-12", "pages": "1382-1387" }, { "id": "authors:b11ww-11n85", "collection": "authors", "collection_id": "b11ww-11n85", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161221-142802182", "type": "book_section", "title": "A Probabilistic Eulerian Approach for Motion Planning of a Large-Scale Swarm of Robots", "book_title": "2016 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)", "author": [ { "family_name": "Bandyopadhyay", "given_name": "Saptarshi", "clpid": "Bandyopadhyay-S" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Hadaegh", "given_name": "Fred Y.", "clpid": "Hadaegh-F-Y" } ], "abstract": "We present a novel method for guiding a large-scale swarm of autonomous agents into a desired formation shape in a distributed and scalable manner. Our Probabilistic Swarm Guidance using Inhomogeneous Markov Chains (PSG-IMC) algorithm adopts an Eulerian framework, where the physical space is partitioned into bins and the swarm's density distribution over each bin is controlled. Each agent determines its bin transition probabilities using a time-inhomogeneous Markov chain. These time-varying Markov matrices are constructed by each agent in real-time using the feedback from the current swarm distribution, which is estimated in a distributed manner. The PSG-IMC algorithm minimizes the expected cost of the transitions per time instant, required to achieve and maintain the desired formation shape, even when agents are added to or removed from the swarm. The algorithm scales well with a large number of agents and complex formation shapes. We demonstrate the effectiveness of this proposed swarm guidance algorithm by using results of numerical simulations and hardware experiments with multiple quadrotors.", "doi": "10.1109/IROS.2016.7759562", "isbn": "978-1-5090-3761-2", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2016-10", "pages": "3822-3829" }, { "id": "authors:a5rwj-28k75", "collection": "authors", "collection_id": "a5rwj-28k75", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20171218-083612231", "type": "book_section", "title": "Attitude Control of the Asteroid Redirect Robotic Mission Spacecraft with a Captured Boulder", "book_title": "AIAA/AAS Astrodynamics Specialist Conference", "author": [ { "family_name": "Falcone", "given_name": "Giusy", "clpid": "Falcone-G" }, { "family_name": "Saxena", "given_name": "Ayush", "clpid": "Saxena-Ayush" }, { "family_name": "Bandyopadhyay", "given_name": "Saptarshi", "clpid": "Bandyopadhyay-S" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Hadaegh", "given_name": "Fred", "clpid": "Hadaegh-F-Y" } ], "abstract": "NASA's Asteroid Redirect Robotic Mission (ARRM) aims to pick up a boulder from of a large asteroid and transport it to a distant retrograde orbit around the Moon for future exploration by a manned mission. In this paper, we present a detailed analysis for one of the main control challenges in ARRM, i.e., three-axis attitude control of the ARRM spacecraft with the captured boulder in the presence of large uncertainties in the physical model of the boulder. We first present a 30 degree-of-freedom nonlinear dynamic model of the ARRM spacecraft and boulder combination. We then linearize this nonlinear model about the nominal operating conditions to study the system's modal properties. A finite element model of the ARRM spacecraft and boulder combination is used to validate our model. We then present linear and nonlinear control laws for the attitude control problem. Both the proportional-derivate based linear controller with lead-lag compensator and roll-off filter and the robust nonlinear tracking control law that tracks a derivative plus proportional-derivate based desired attitude trajectory give robust performance over the range of boulder parameters. We present a detailed comparison of these control laws and also present some design guidelines for the ARRM spacecraft.", "doi": "10.2514/6.2016-5645", "isbn": "978-1-62410-445-9", "publisher": "American Institute of Aeronautics and Astronautics", "publication_date": "2016-09", "pages": "Art. No. 2016-5645" }, { "id": "authors:1pv9c-acf52", "collection": "authors", "collection_id": "1pv9c-acf52", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20171218-084716717", "type": "book_section", "title": "Fast Motion Planning for Agile Space Systems with Multiple Obstacles", "book_title": "AIAA/AAS Astrodynamics Specialist Conference", "author": [ { "family_name": "Baldini", "given_name": "Francesca", "clpid": "Baldini-F" }, { "family_name": "Bandyopadhyay", "given_name": "Saptarshi", "clpid": "Bandyopadhyay-S" }, { "family_name": "Foust", "given_name": "Rebecca", "orcid": "0000-0003-1470-1716", "clpid": "Foust-Rebecca" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Rahmani", "given_name": "Amir", "clpid": "Rahmani-A" }, { "family_name": "de la Croix", "given_name": "Jean-Pierre", "clpid": "de-la-Croix-J-P" }, { "family_name": "Bacula", "given_name": "Alexandra", "clpid": "Bacula-A" }, { "family_name": "Chilan", "given_name": "Christian M.", "clpid": "Chilan-Christian-M" }, { "family_name": "Hadaegh", "given_name": "Fred", "clpid": "Hadaegh-F-Y" } ], "abstract": "In this paper, we develop a novel algorithm for spacecraft trajectory planning in an environment cluttered with many geometrically-fixed obstacles. The Spherical Expansion and Sequential Convex Programming (SE-SCP) algorithm first uses a spherical-expansion-based sampling algorithm to explore the workspace. Once a path is found from the start position to the goal position, the algorithm generates a locally optimal trajectory within the homotopy class using sequential convex programming. If the number of samples tends to infinity, then the SE-SCP trajectory converges to the globally optimal trajectory in the workspace. The SE-SCP algorithm is computationally efficient, therefore it can be used for real-time applications on resource-constrained systems. We also present results of numerical simulations and comparisons with existing algorithms.", "doi": "10.2514/6.2016-5683", "isbn": "978-1-62410-445-9", "publisher": "American Institute of Aeronautics and Astronautics", "publication_date": "2016-09", "pages": "Art. No. 2016-5683" }, { "id": "authors:8xnyw-9zt91", "collection": "authors", "collection_id": "8xnyw-9zt91", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20171214-075651822", "type": "book_section", "title": "Autonomous In-Orbit Satellite Assembly from a Modular Heterogeneous Swarm using Sequential Convex Programming", "book_title": "AIAA/AAS Astrodynamics Specialist Conference", "author": [ { "family_name": "Foust", "given_name": "Rebecca C.", "orcid": "0000-0003-1470-1716", "clpid": "Foust-Rebecca" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Hadaegh", "given_name": "Fred Y.", "clpid": "Hadaegh-F-Y" } ], "abstract": "This paper presents a decentralized guidance and control scheme to combine a heterogeneous swarm of component satellites into a large satellite structure. Building on prior work, the Swarm Orbital Construction Algorithm was made more realistic and correct by changing the docking and collision avoidance criteria and implementing a nonlinear correction in the convex optimization solver. The algorithm was then extended to function in a simulated perturbed 6-DOF spacecraft environment. This required the addition of an attitude barrier function to the target assignment algorithm as discussed in the previous paper, as well as the selection of a realistic range for actuator performance and spacecraft shape parameters. Simulation results are presented using a swarm of CubeSat-class satellites.", "doi": "10.2514/6.2016-5271", "isbn": "978-1-62410-445-9", "publisher": "American Institute of Aeronautics and Astronautics", "publication_date": "2016-09", "pages": "Art. No. 2016-5271" }, { "id": "authors:0bbyd-tan16", "collection": "authors", "collection_id": "0bbyd-tan16", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161221-074429456", "type": "book_section", "title": "Bat Bot (B2), a biologically inspired flying machine", "book_title": "2016 IEEE International Conference on Robotics and Automation (ICRA)", "author": [ { "family_name": "Ramezani", "given_name": "Alireza", "orcid": "0000-0002-3391-5288", "clpid": "Ramezani-Alireza" }, { "family_name": "Shi", "given_name": "Xichen", "clpid": "Shi-Xichen" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Hutchinson", "given_name": "Seth", "orcid": "0000-0002-3949-6061", "clpid": "Hutchinson-Seth" } ], "abstract": "It is challenging to analyze the aerial locomotion of bats because of the complicated and intricate relationship between their morphology and flight capabilities. Developing a biologically inspired bat robot would yield insight into how bats control their body attitude and position through the complex interaction of nonlinear forces (e.g., aerodynamic) and their intricate musculoskeletal mechanism. The current work introduces a biologically inspired soft robot called Bat Bot (B2). The overall system is a flapping machine with 5 Degrees of Actuation (DoA). This work reports on some of the preliminary untethered flights of B2. B2 has a nontrivial morphology and it has been designed after examining several biological bats. Key DoAs, which contribute significantly to bat flight, are picked and incorporated in B2's flight mechanism design. These DoAs are: 1) forelimb flapping motion, 2) forelimb mediolateral motion (folding and unfolding) and 3) hindlimb dorsoventral motion (upward and downward movement).", "doi": "10.1109/ICRA.2016.7487491", "isbn": "978-1-4673-8026-3", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2016-05", "pages": "3219-3226" }, { "id": "authors:sxvpv-1z891", "collection": "authors", "collection_id": "sxvpv-1z891", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170113-132202589", "type": "book_section", "title": "Strain actuated solar-arrays for precision pointing of spacecraft", "book_title": "Guidance, Navigation, and Control, 2016", "author": [ { "family_name": "Alvarez-Salazar", "given_name": "Oscar", "clpid": "Alvarez-Salazar-O-S" }, { "family_name": "Aldrich", "given_name": "Jack", "clpid": "Aldrich-J" }, { "family_name": "Filipe", "given_name": "Nuno", "clpid": "Filipe-N" }, { "family_name": "Allison", "given_name": "James", "clpid": "Allison-J" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "contributor": [ { "family_name": "Chart", "given_name": "David A.", "clpid": "Chart-D-A" } ], "abstract": "Next generation telescopes for space exploration are being planned with unprecedented levels\nof pointing and wavefront stability as science enabling capabilities - i.e., sub-milli-arcsecond\nclass pointing, and pico-meter class RMS wave-front error). Current methodologies for attaining\nthese levels of stability are approaching the limit of what is possible with the use\nof isolation, intensive and risky structural dynamic tailoring, exquisite broad-band Attitude\nControl System (ACS) sensors and actuators, and ultra-precise fast steering mirrors commanded\nto compensate for pointing errors through feedback of camera measurements. This\npaper explores the benefits of using Strain Actuated Solar Arrays (SASA) - currently under\nResearch at the Jet Propulsion Laboratory and the University of Illinois Urbana Champagne\n- in new ACS architectures for applications requiring very tight precision pointing of a SC\nand on-board instrumentation. A strain actuated solar array has the following characteristics:\n(1) Strain actuation and sensing is distributed throughout the SA panels to obtain control authority\nand observability over the strain state of the SA\u2013enabling SA jitter control. (2) Large\nmotion (up to 10 degrees or relative motion) strain based mechanisms are used in between\nSA panels and in between the SC and the solar array\u2013enables SC slewing and limited momentum\nmanagement. (3) The mechanical (i.e., stiffness and configuration) and inertia/mass\nproperties of the SA have been designed to optimize its ability to control its vibrations and\nthe vibration and attitude of the host SC. This paper discusses ACS architectures that use the\nabove SASA system while avoiding the use of the Reaction Wheel Actuator (RWA) during\nkey science observation periods. The RWA being the dominant source of pointing jitter and\nwave front jitter in a telescope based observatory; hence, not flying RWAs amounts to not\nflying the main source of jitter! At least two architectures based on the SASA system are\nstudied - one is an earth orbiter, the other is assumed to be in an L2 orbit. Simulation results\nfor one of these cases are discussed along with what developments are needed going forward\nto enable the use of this technology.", "isbn": "9780877036319", "publisher": "American Astronautical Society", "place_of_publication": "San Diego, CA", "publication_date": "2016-02", "pages": "Art. No. AAS 16-137" }, { "id": "authors:gpdny-rth26", "collection": "authors", "collection_id": "gpdny-rth26", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161220-143603084", "type": "book_section", "title": "Robotic Herding Using Wavefront Algorithm: Performance and Stability", "book_title": "AIAA Guidance, Navigation, and Control Conference, 2016", "author": [ { "family_name": "Gade", "given_name": "Shripad", "clpid": "Gade-Shripad" }, { "family_name": "Paranjape", "given_name": "Aditya A.", "orcid": "0000-0002-3164-3215", "clpid": "Paranjape-A-A" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "This paper is concerned with robotic herding of a swarm of birds by another adversarial agent, referred\nto as the pursuer. The objective of herding is to prevent the birds from entering a specified volume of space,\nsuch as the air space around an airport. The n-Wavefront algorithm was introduced by the authors in a\nprior paper to enable herding of a swarm of birds using a robotic unmanned aerial vehicle. In this paper,\nthe performance and stability characteristics are analyzed using tools from linear and nonlinear stability\ntheory, with the aim of proving its performance and identifying the permissible and optimum values of the\ncontrol parameters. It is shown that, using the n-Wavefront algorithm, a pursuer can successfully maneuver\nthe birds around the prescribed perimeter while ensuring that the swarm does not undergo fragmentation\nas a result of its response to the presence of the pursuer.", "doi": "10.2514/6.2016-1378", "isbn": "978-1-62410-389-6", "publisher": "American Institute of Aeronautics and Astronautics (AIAA)", "place_of_publication": "Reston, VA", "publication_date": "2016-01-08", "pages": "Art. No. 2016-1378" }, { "id": "authors:knwvh-d7f12", "collection": "authors", "collection_id": "knwvh-d7f12", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161130-080521015", "type": "book_section", "title": "Modeling and Nonlinear Flight Controller Synthesis of a Bat-Inspired Micro Aerial Vehicle", "book_title": "AIAA Guidance, Navigation, and Control Conference 2016", "author": [ { "family_name": "Ramezani", "given_name": "Alireza", "orcid": "0000-0002-3391-5288", "clpid": "Ramezani-Alireza" }, { "family_name": "Shi", "given_name": "Xichen", "clpid": "Shi-Xichen" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Hutchinson", "given_name": "Seth", "orcid": "0000-0002-3949-6061", "clpid": "Hutchinson-Seth" } ], "abstract": "This work examines the control of nonlinear dynamic systems to synthesize a flight controller for Bat Bot (B2). B2 is a bat-inspired Micro Aerial Vehicle (MAV) which has\narticulated arm wings with several actuated and passive joints. B2 is designed to mimic the flight apparatus of actual biological bats, which is distinguished from other animals such as birds because bats employ numerous joints\u2013more than 20 joint angles per each wing\u2013and exhibit sophisticated motion patterns. B2 has significantly fewer degrees of freedom (DoF) than biological bats and the existing movements in the mechanism of B2 are: flapping\nmotion of the wings, folding and unfolding of the wings and dorsoventral movements of the legs. The current work contributes to recent attempts to produce autonomous flapping flight motions in a bio-inspired robot with nontrivial morphology. This work uses the Lagrange framework to develop a nonlinear dynamic model for B2, and it proposes a nonlinear controller based on the theory of singular perturbation in order to track desired attitude angles.", "doi": "10.2514/6.2016-1376", "isbn": "978-1-62410-389-6", "publisher": "American Institute of Aeronautics and Astronautics (AIAA)", "place_of_publication": "Reston, VA", "publication_date": "2016-01", "pages": "Art. No. 2016-1376" }, { "id": "authors:2jd2y-8mc90", "collection": "authors", "collection_id": "2jd2y-8mc90", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161220-115042791", "type": "book_section", "title": "Co-Design of Strain-Actuated Solar Arrays for Precision Pointing and Jitter Reduction", "book_title": "Structures, Structural Dynamics, and Materials Conference 57th AIAA/ASCE/AHS/ASC", "author": [ { "family_name": "Chilan", "given_name": "Christian M.", "clpid": "Chilan-Christian-M" }, { "family_name": "Herber", "given_name": "Daniel R.", "clpid": "Herber-Daniel-R" }, { "family_name": "Nakka", "given_name": "Yashwanth K.", "orcid": "0000-0001-7897-3644", "clpid": "Nakka-Yashwanth-K" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Allison", "given_name": "James T.", "clpid": "Allison-James-T" }, { "family_name": "Aldrich", "given_name": "Jack B.", "clpid": "Aldrich-Jack-B" }, { "family_name": "Alvarez-Salazar", "given_name": "Oscar S.", "clpid": "Alvarez-Salazar-O-S" } ], "abstract": "Many important spacecraft operations require precision pointing such as space astronomy and high-rate communications. Traditionally, reaction wheels have been used for this purpose but they have been considered unreliable for many missions. This work presents the use strain-actuated solar arrays (SASA) for precision pointing and jitter reduction. Piezoelectric actuators can achieve higher precision and bandwidth than reaction wheels, and they can also provide quiet operation for sensitive instruments. The representation of the array dynamics in the studies presented here is based on Euler-Bernoulli beam theory for high-fidelity simulations. This work also presents a methodology for the combined design of distributed structural geometry for the arrays and distributed control system design. The array geometry design allows for a distributed thickness profile, and the control design determines the distributed moment on the array. Fundamental limits on slew magnitude are found using pseudo-rigid body dynamic model (PRBDM) theory. A parametric study based on a representative spacecraft model demonstrates the validity of the proposed approach and illustrates optimal design trends.", "doi": "10.2514/MSDM16", "isbn": "978-1-62410-392-6", "publisher": "American Institute of Aeronautics and Astronautics (AIAA)", "place_of_publication": "Reston, VA", "publication_date": "2016-01", "pages": "Art. No.-2016" }, { "id": "authors:9c8hf-m7j61", "collection": "authors", "collection_id": "9c8hf-m7j61", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161222-124053440", "type": "book_section", "title": "Output feedback stabilization of linear PDEs with finite dimensional input-output maps and Kelvin-Voigt damping", "book_title": "54th IEEE Conference on Decision and Control (CDC)", "author": [ { "family_name": "Paranjape", "given_name": "Aditya A.", "orcid": "0000-0002-3164-3215", "clpid": "Paranjape-A-A" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "In this paper, we consider systems of partial differential equations with a finite relative degree between the input and the output. In such systems, an output feedback controller can be constructed to regulate the output with the desired convergence properties. Although the zero dynamics are infinite dimensional, we show that the controller alters the boundary conditions in such a way that it leads to a predictable expansion in the stable operating envelope of the system. Moreover, the expansion of the stable envelope depends only on the boundary conditions and the structure of the PDE, and is independent of the system parameters. The methodology is extended to output tracking and time-varying forcing functions as well. The phenomenon investigated in the paper is quite unique to partial differential equations and without any parallel in systems of ODEs.", "doi": "10.1109/CDC.2015.7402291", "isbn": "978-1-4799-7886-1", "publisher": "IEEE", "place_of_publication": "New York, NY", "publication_date": "2015-12", "pages": "578-583" }, { "id": "authors:hwvkt-rx587", "collection": "authors", "collection_id": "hwvkt-rx587", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170117-081205300", "type": "book_section", "title": "Lagrangian Modeling and Flight Control of Articulated-Winged Bat Robot", "book_title": "International Conference on Intelligent Robots and Systems (IROS), 2015", "author": [ { "family_name": "Ramezani", "given_name": "Alireza", "orcid": "0000-0002-3391-5288", "clpid": "Ramezani-Alireza" }, { "family_name": "Shi", "given_name": "Xichen", "clpid": "Shi-Xichen" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Hutchinson", "given_name": "Seth", "orcid": "0000-0002-3949-6061", "clpid": "Hutchinson-Seth" } ], "abstract": "This paper presents a systematic flight controller design based on the mathematics of parametrized manifolds and calculus of variations for the Bat Bot (B2), which possesses many articulated wings. Wing kinematics and morphological properties are crucial in the powered flight of flying vertebrates. The articulated skeleton of these mammals, which contains many degrees of actuation and underactuation, has made it difficult to understand the connection between the bat's flight dynamics and its intricate array of physiological and morphological specializations. B2 is a biomimetic micro aerial vehicle (MAV) that possesses similar morphological properties to a bat in order to duplicate bats powered ballistic motion. In an effort to design the advanced flight control algorithm for B2, this paper reports two major contributions. First, a systematic mathematical framework is introduced that evaluates the holonomically-constrained Lagrangian model of a flapping robot with specified active and passive degrees of freedom (DoF) in order to locate physically feasible and biologically meaningful periodic solutions using optimization. These are parametrized constraint manifolds; the flapping wing dynamics are governed by these manifolds. Second, calculus of variations and the well-recognized method of inverse dynamics are applied in order to synthesize the flight control algorithm for the flapping wings.", "doi": "10.1109/IROS.2015.7353772", "isbn": "978-1-4799-9994-1", "publisher": "IEEE", "place_of_publication": "New York, NY", "publication_date": "2015-10", "pages": "2867-2874" }, { "id": "authors:1hbt0-g1r39", "collection": "authors", "collection_id": "1hbt0-g1r39", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170120-153909449", "type": "book_section", "title": "New Guidance, Navigation, and Control Technologies for Formation Flying Spacecraft and Planetary Landing", "book_title": "Advances in Control System Technology for Aerospace Applications", "author": [ { "family_name": "Hadaegh", "given_name": "Fred Y.", "clpid": "Hadaegh-F-Y" }, { "family_name": "Johnson", "given_name": "Andrew E.", "clpid": "Johnson-A-E" }, { "family_name": "Bayard", "given_name": "David S.", "clpid": "Bayard-D-S" }, { "family_name": "A\u00e7\u0131kme\u015fe", "given_name": "Beh\u00e7et", "clpid": "A\u00e7\u0131kme\u015fe-Beh\u00e7et" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Mehra", "given_name": "Raman K.", "clpid": "Mehra-Raman-K" } ], "contributor": [ { "family_name": "Feron", "given_name": "E.", "clpid": "Feron-E" } ], "abstract": "This chapter describes recent advancements in the areas of guidance, navigation, and control of distributed spacecraft systems or spacecraft formation flying of swarms of 100-gram class spacecraft and planetary landing. A review of advances in perception technologies for on-board hazard detection and terrain relative navigation is presented. The second part of this chapter is devoted to the discussion of innovative research on spacecraft swarms. Spacecraft swarms, comprised of hundreds to thousands of small spacecraft will push the frontier of the existing formation flying concepts by maximizing the benefits of distributed spacecraft systems. Novel control strategies of handling such a large spacecraft network are presented by employing synchronization control on adaptive graphs and probabilistic swarm guidance strategies. Furthermore, new filtering techniques that enable tracking of a large number of space objects are discussed.", "doi": "10.1007/978-3-662-47694-9_2", "isbn": "978-3-662-47693-2", "publisher": "Springer", "place_of_publication": "Berlin Heidelberg", "publication_date": "2015-09-17", "pages": "49-80" }, { "id": "authors:9awsf-w3a26", "collection": "authors", "collection_id": "9awsf-w3a26", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161221-090449955", "type": "book_section", "title": "Dynamics and Control of Tethered Formation Flight Spacecraft Using the SPHERES Testbed", "book_title": "AIAA Guidance, Navigation, and Control Conference and Exhibit, 2005", "author": [ { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Kong", "given_name": "Edmund", "clpid": "Kong-Edmund" }, { "family_name": "Miller", "given_name": "David", "orcid": "0000-0001-6099-0614", "clpid": "Miller-D-W" } ], "abstract": "This paper elaborates on the theory and experiment of controlling tethered spacecraft formation without depending on thrusters. In dealing with such underactuated systems,\nmuch emphasis is placed on complete decentralization of the control and estimation algorithms in order to reduce the dimensionality and complication. The nonlinear equations\nof motions of multi-vehicle tethered spacecraft are derived by Lagrange's equations. Decentralization is then realized by the diagonalization technique and its stability is proven\nby contraction theory. The preliminary analysis predicts unstable dynamics depending on the direction of the tether motor. The controllability analysis indicates that both array resizing and spin-up are fully controllable only by the reaction wheels and the tether motor, thereby eliminating the need for thrusters. Based upon this analysis, gain-scheduling LQR controllers and nonlinear controllers by feedback linearization have been successfully implemented into the tethered SPHERES testbed, and tested at the NASA MSFCs flat floor facility using two and three SPHERES configurations. The relative sensing mechanism employing the ultrasound ranging system and the inertial gyro is also described.", "doi": "10.2514/6.2005-6089", "isbn": "978-1-62410-056-7", "publisher": "American Institute of Aeronautics and Astronautics (AIAA)", "place_of_publication": "Reston, VA", "publication_date": "2015-08-18", "pages": "Art. No. 2005-6089" }, { "id": "authors:wg0t5-4cv75", "collection": "authors", "collection_id": "wg0t5-4cv75", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170113-153442532", "type": "book_section", "title": "Nonlinear Attitude Control of Spacecraft with a captured asteroid", "author": [ { "family_name": "Bandyopadhyay", "given_name": "Saptarshi", "clpid": "Bandyopadhyay-S" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "One of the main control challenges of National Aeronautics and Space Administration's\nproposed Asteroid Redirect Mission (ARM) is to stabilize and control the attitude of the\nspacecraft-asteroid combination in the presence of large uncertainty in the physical model of\na captured asteroid. We present a new robust nonlinear tracking control law that guarantees\nglobal exponential convergence of the system's attitude trajectory to the desired attitude trajectory.\nIn the presence of modeling errors and disturbances, this control law is finite-gain\nL_p stable and input-to-state stable. We also present a few extensions of this control law,\nsuch as exponential tracking control on SO(3) and integral control, and show its relation to\nthe well-known tracking control law for Euler-Lagrangian systems. We show that the resultant\ndisturbance torques for control laws that use feed-forward cancellation is comparable to\nthe maximum control torque of the conceptual ARM spacecraft and such control laws are\ntherefore not suitable. We then numerically compare the performance of multiple viable attitude\ncontrol laws, including the robust nonlinear tracking control law, nonlinear adaptive\ncontrol, and derivative plus proportional-derivative linear control. We conclude that under\nvery small modeling uncertainties, which can be achieved using online system identification,\nthe robust nonlinear tracking control law that guarantees globally exponential convergence\nto the fuel-optimal reference trajectory is the best strategy as it consumes the least amount\nof fuel. On the other hand, in the presence of large modeling uncertainties and actuator saturations,\na simple derivative plus proportional-derivative (D+PD) control law is effective, and\nthe performance can be further improved by using the proposed nonlinear tracking control\nlaw that tracks a (D+PD)-control-based desired attitude trajectory. We conclude this paper\nwith specific design guidelines for the ARM spacecraft for efficiently stabilizing a tumbling\nasteroid and spacecraft combination.", "publisher": "Journal of Guidance Control and Dynamics", "publication_date": "2015-06" }, { "id": "authors:5qr88-zs308", "collection": "authors", "collection_id": "5qr88-zs308", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161221-075702098", "type": "book_section", "title": "Omnidirectional-vision-based estimation for containment detection of a robotic mower", "book_title": "2015 IEEE International Conference on Robotics and Automation (ICRA)", "author": [ { "family_name": "Yang", "given_name": "Junho", "clpid": "Yang-Junho" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Hutchinson", "given_name": "Seth", "orcid": "0000-0002-3949-6061", "clpid": "Hutchinson-Seth" }, { "family_name": "Johnson", "given_name": "David", "clpid": "Johnson-David" }, { "family_name": "Kise", "given_name": "Michio", "clpid": "Kise-Michio" } ], "abstract": "In this paper, we present an omnidirectional-vision-based localization and mapping system which can detect whether a robotic mower is contained in a permitted area. We exploit a robot-centric mapping framework that exploits a differential equation of motion of the landmarks, which are referenced with respect to the robot body frame. The estimator in our system generates a 3D point-based map with landmarks. Concurrently, the estimator defines a boundary of the mowing area with the estimated trajectory of the mower. The estimated boundary and the landmark map are provided for the estimation of the mowing location and for the containment detection. We validate the effectiveness of our system through numerical simulations and present the results of the outdoor experiment that we conducted with our robotic mower.", "doi": "10.1109/ICRA.2015.7140090", "isbn": "978-1-4799-6923-4", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2015-05", "pages": "6344-6351" }, { "id": "authors:mycq9-k4969", "collection": "authors", "collection_id": "mycq9-k4969", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170120-151859268", "type": "book_section", "title": "Swarm Assignment and Trajectory Optimization Using Variable-Swarm, Distributed Auction Assignment and Model Predictive Control", "book_title": "AIAA Guidance, Navigation, and Control Conference 2015", "author": [ { "family_name": "Morgan", "given_name": "Daniel", "clpid": "Morgan-Daniel" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Hadaegh", "given_name": "Fred Y.", "clpid": "Hadaegh-F-Y" } ], "abstract": "This paper presents a distributed, guidance and control algorithm for reconfiguring swarms composed of hundreds to thousands of agents with limited communication and\ncomputation capabilities. This algorithm solves both the optimal assignment and collision- free trajectory generation for swarms, in an integrated manner, when given the desired shape of the swarm (without pre-assigned terminal positions). The optimal assignment problem is solved using a distributed auction assignment that can vary the number of target positions in the assignment, and the collision-free trajectories are generated using sequential convex programming. Finally, model predictive control is used to solve the assignment and trajectory generation in real time using a receding horizon. The model predictive control formulation uses current state measurements to resolve for the optimal assignment\nand trajectory. The implementation of the distributed auction algorithm and sequential convex programming using model predictive control produces the swarm assignment and\ntrajectory optimization algorithm that transfers a swarm of spacecraft to a desired shape in a distributed fashion. Once the desired shape is uploaded to the swarm, the algorithm determines where each spacecraft goes and how it should get there in a fuel-efficient, collision-free manner.", "doi": "10.2514/6.2015-0599", "isbn": "978-1-62410-339-1", "publisher": "American Institute of Aeronautics and Astronautics (AIAA)", "place_of_publication": "Reston, VA", "publication_date": "2015-01", "pages": "Art. No. 2015-0599" }, { "id": "authors:v8xr6-vs182", "collection": "authors", "collection_id": "v8xr6-vs182", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161130-083605025", "type": "book_section", "title": "A Review of Impending Small Satellite Formation Flying Missions", "book_title": "53rd AIAA Aerospace Sciences Meeting", "author": [ { "family_name": "Bandyopadhyay", "given_name": "Saptarshi", "clpid": "Bandyopadhyay-S" }, { "family_name": "Subramanian", "given_name": "Giri P.", "clpid": "Subramanian-G-P" }, { "family_name": "Foust", "given_name": "Rebecca", "orcid": "0000-0003-1470-1716", "clpid": "Foust-Rebecca" }, { "family_name": "Morgan", "given_name": "Daniel", "clpid": "Morgan-Daniel" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Hadaegh", "given_name": "Fred Y.", "clpid": "Hadaegh-F-Y" } ], "abstract": "Small satellites, like popular nanosatellite platforms called CubeSats, are suitable for formation flying missions because of their modular nature and low cost. This paper presents a review of thirty-nine missions, using multiple small satellites, in various stages of development. These missions are categorized based on their mission type, mission status, number of satellites, leading organization, funding source, and requirement for constellation or\nformation flying. We conclude that Earth science related missions are the most popular, while most multi-satellite missions only require a constellation. Although six missions aim to demonstrate formation flying capability in space using two to three small satellites, there are currently only two formation flying missions planning to use four or more small satellites.", "doi": "10.2514/6.2015-1623", "isbn": "978-1-62410-343-8", "publisher": "American Institute of Aeronautics and Astronautics (AIAA)", "place_of_publication": "Reston, VA", "publication_date": "2015-01", "pages": "Art. No. 2015-1623" }, { "id": "authors:88a44-wnr37", "collection": "authors", "collection_id": "88a44-wnr37", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161130-140551043", "type": "book_section", "title": "Attitude Control and Stabilization of Spacecraft with a Captured Asteroid", "author": [ { "family_name": "Bandyopadhyay", "given_name": "Saptarshi", "clpid": "Bandyopadhyay-S" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Hadaegh", "given_name": "Fred Y.", "clpid": "Hadaegh-F-Y" } ], "abstract": "National Aeronautics and Space Administration's Asteroid Redirect Mission (ARM) aims to capture a Near Earth Orbit (NEO) asteroid or a piece of a large asteroid and transport it to the Earth{Moon system. In this paper, we provide a detailed analysis\nof one of the main control challenges for the first ARM mission concept, namely despinning and three-axis stabilizing the asteroid and spacecraft combination after the ARM spacecraft captures the tumbling NEO asteroid. We first show that control laws, which explicitly use the dynamics of the system in their control law equation, encounter a fundamental limitation due to modeling uncertainties. We show that in the presence of large\nmodeling uncertainties, the resultant disturbance torque for such control laws may well exceed the maximum control torque of the conceptual ARM spacecraft. We then numerically compare the performance of three viable control laws: the robust nonlinear tracking control law, the adaptive nonlinear tracking control law, and the simple derivative plus proportional-derivative linear control strategy. We conclude that under very small mod-\neling uncertainties, which can be achieved using online system identification, the robust nonlinear tracking control law guarantees exponential convergence to the fuel-optimal reference trajectory and hence consumes the least fuel. On the other hand, in the presence of large modeling uncertainties, measurement errors, and actuator saturations, the best strategy for stabilizing the asteroid and spacecraft combination is to first despin the system using a derivative (rate damping) linear control law and then stabilize the system in the desired orientation using the simple proportional-derivative linear control law. More-over, the fuel consumed by the conceptual ARM spacecraft using these control strategies is upper bounded by 300 kg for the nominal range of NEO asteroid parameters. We conclude this paper with specific design guidelines for the ARM spacecraft for efficiently stabilizing the tumbling NEO asteroid and spacecraft combination.", "doi": "10.2514/6.2015-0596", "publisher": "American Institute of Aeronautics and Astronautics (AIAA)", "publication_date": "2015-01" }, { "id": "authors:6w8pf-agr93", "collection": "authors", "collection_id": "6w8pf-agr93", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170214-070946630", "type": "book_section", "title": "Herding a Flock of Birds Approaching an Airport Using an Unmanned Aerial Vehicle", "book_title": "AIAA Guidance, Navigation, and Control Conference 2015", "author": [ { "family_name": "Gade", "given_name": "Shripad", "clpid": "Gade-Shripad" }, { "family_name": "Paranjape", "given_name": "Aditya A.", "orcid": "0000-0002-3164-3215", "clpid": "Paranjape-A-A" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "The problem of herding a flock of birds is posed in a graph theoretic framework. A novel algorithm, called the n-wavefront algorithm, Is developed for enabling a single unmanned aerial vehicle to herd a flock of birds to a desired point. The technique is applied to the problem of diverting a flock of birds approaching an airport away from a protected zone around the airport. The n-wavefront algorithm is demonstrated in simulation and compared with existing strategies using graph-based metrics.", "doi": "10.2514/6.2015-1540", "isbn": "978-1-5108-0109-7", "publisher": "American Institute of Aeronautics and Astronautics (AIAA)", "place_of_publication": "Reston, VA", "publication_date": "2015-01", "pages": "Art. No. 2015-1540" }, { "id": "authors:5gyhs-m6937", "collection": "authors", "collection_id": "5gyhs-m6937", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161130-153238963", "type": "book_section", "title": "Information-Driven Systems Engineering Study of a Formation Flying Demonstration Mission using Six CubeSats", "author": [ { "family_name": "Subramanian", "given_name": "Giri P.", "clpid": "Subramanian-G-P" }, { "family_name": "Foust", "given_name": "Rebecca", "orcid": "0000-0003-1470-1716", "clpid": "Foust-Rebecca" }, { "family_name": "Chen", "given_name": "Derek", "clpid": "Chen-Derek" }, { "family_name": "Chan", "given_name": "Stanley", "clpid": "Chan-Stanley" }, { "family_name": "Taleb", "given_name": "Younes", "clpid": "Taleb-Younes" }, { "family_name": "Rogers", "given_name": "Dayne L.", "clpid": "Rogers-Dayne-L" }, { "family_name": "Kokkat", "given_name": "Jobin", "clpid": "Kokkat-Jobin" }, { "family_name": "Bandyopadhyay", "given_name": "Saptarshi", "clpid": "Bandyopadhyay-S" }, { "family_name": "Morgan", "given_name": "Daniel", "clpid": "Morgan-Daniel" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Hadaegh", "given_name": "Fred Y.", "clpid": "Hadaegh-F-Y" } ], "abstract": "Small satellites are suitable for formation flying missions where a large number of spacecraft serve as distributed sensors for applications like synthetic aperture radar, interferometry, etc. A survey of existing or proposed small satellite missions concludes that there is a dearth of formation flying missions using four or more spacecraft that require formation maintenance. This paper presents a systems engineering based design of a formation flying technology demonstration mission that requires precise formation maintenance and reconfigurations and highlights the challenges that need to be overcome for its successful implementation. The goal of this paper is to provide directions for future research and development in spacecraft formation flying technologies.", "doi": "10.2514/6.2015-2043", "publisher": "American Institute of Aeronautics and Astronautics (AIAA)", "publication_date": "2015-01" }, { "id": "authors:63rn3-sht84", "collection": "authors", "collection_id": "63rn3-sht84", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161220-110956591", "type": "book_section", "title": "Dyadic perturbation observer framework for control of a class of nonlinear PDE/ODE systems", "book_title": "53rd IEEE Conference on Decision and Control", "author": [ { "family_name": "Paranjape", "given_name": "Aditya A.", "orcid": "0000-0002-3164-3215", "clpid": "Paranjape-A-A" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "This paper presents the general theory of the dyadic perturbation observer framework as a generic method for controlling a class of nonlinear systems described by partial and/or ordinary differential equations. The method is particularly applicable to boundary control problems for systems described by partial differential equations. Conditions for closed-loop stability and robustness are derived using finite-gain L stability theory, and the results are further specialized for finite dimensional systems.", "doi": "10.1109/CDC.2014.7039702", "isbn": "978-1-4673-6090-6", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2014-12", "pages": "2065-2070" }, { "id": "authors:fewdn-93s06", "collection": "authors", "collection_id": "fewdn-93s06", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170109-103702672", "type": "book_section", "title": "Probabilistic swarm guidance using optimal transport", "book_title": "2014 IEEE Conference on Control Applications (CCA)", "author": [ { "family_name": "Bandyopadhyay", "given_name": "Saptarshi", "clpid": "Bandyopadhyay-S" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Hadaegh", "given_name": "Fred Y.", "clpid": "Hadaegh-F-Y" } ], "abstract": "Probabilistic swarm guidance enables autonomous agents to generate their individual trajectories independently so that the entire swarm converges to the desired distribution shape. In contrast with previous homogeneous or inhomogeneous Markov chain based approaches [1], this paper presents an optimal transport based approach which guarantees faster convergence, minimizes a given cost function, and reduces the number of transitions for achieving the desired formation. Each agent first estimates the current swarm distribution by communicating with neighboring agents and using a consensus algorithm and then solves the optimal transport problem, which is recast as a linear program, to determine its transition probabilities. We discuss methods for handling motion constraints and also demonstrate the superior performance of the proposed algorithm by numerically comparing it with existing Markov chain based strategies.", "doi": "10.1109/CCA.2014.6981395", "isbn": "978-1-4799-7409-2", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2014-10", "pages": "498-505" }, { "id": "authors:ftbf3-jrr57", "collection": "authors", "collection_id": "ftbf3-jrr57", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161222-115746072", "type": "book_section", "title": "Probabilistic guidance of distributed systems using sequential convex programming", "book_title": "2014 IEEE/RSJ International Conference on Intelligent Robots and Systems", "author": [ { "family_name": "Morgan", "given_name": "Daniel", "clpid": "Morgan-Daniel" }, { "family_name": "Subramanian", "given_name": "Giri Prashanth", "clpid": "Subramanian-G-P" }, { "family_name": "Bandyopadhyay", "given_name": "Saptarshi", "clpid": "Bandyopadhyay-S" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Hadaegh", "given_name": "Fred Y.", "clpid": "Hadaegh-F-Y" } ], "abstract": "In this paper, we integrate, implement, and validate formation flying algorithms for a large number of agents using probabilistic guidance of distributed systems with inhomogeneous Markov chains and model predictive control with sequential convex programming. Using an inhomogeneous Markov chain, each agent determines its target position during each iteration in a statistically independent manner while the distributed system converges to the desired formation. Moreover, the distributed system is robust to external disturbances or damages to the formation. Once the target positions are assigned, an optimal control problem is formulated to ensure that the agents reach the target positions while avoiding collisions. This problem is solved using sequential convex programming to determine optimal, collision-free trajectories and model predictive control is implemented to update these trajectories as new state information becomes available. Finally, we validate the probabilistic guidance of distributed systems and model predictive control algorithms using the formation flying testbed.", "doi": "10.1109/IROS.2014.6943103", "isbn": "978-1-4799-6934-0", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2014-09", "pages": "3850-3857" }, { "id": "authors:0qq3f-88822", "collection": "authors", "collection_id": "0qq3f-88822", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161201-103533605", "type": "book_section", "title": "Robust Tunable Transcriptional Oscillators Using Dynamic Inversion", "book_title": "A Systems Theoretic Approach to Systems and Synthetic Biology I: Models and System Characterizations", "author": [ { "family_name": "Kulkarni", "given_name": "Vishwesh V.", "clpid": "Kulkarni-V-V" }, { "family_name": "Paranjape", "given_name": "Aditya A.", "orcid": "0000-0002-3164-3215", "clpid": "Paranjape-A-A" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "contributor": [ { "family_name": "Kulkarni", "given_name": "Vishwesh V.", "clpid": "Kulkarni-V-V" }, { "family_name": "Stan", "given_name": "Guy-Bart", "clpid": "Stan-G-B" }, { "family_name": "Raman", "given_name": "Karthik", "clpid": "Raman-K" } ], "abstract": "We present a theory and associated algorithms to synthesize controllers that may be used to build robust tunable oscillations in biological networks. As an illustration, we build robust tunable oscillations in the celebrated repressilator synthesized by Elowitz and Leibler. The desired oscillations in a set of mRNA's and proteins are obtained by injecting an oscillatory input as a reference and by synthesizing a dynamic inversion based tracking controller. This approach ensures that the repressilator can exhibit oscillations irrespective of (1) the maximum number of proteins per cell and (2) the ratio of the protein lifetimes to the mRNA lifetimes. The frequency and the amplitude of at least one output (either mRNA or protein) can now be controlled arbitrarily. In addition, we characterize the L_2 gain stability of this 3-node network and generalize it to the case of N-node networks.", "doi": "10.1007/978-94-017-9041-3_4", "isbn": "978-94-017-9040-6", "publisher": "Springer Netherlands", "place_of_publication": "Berlin", "publication_date": "2014-07-04", "pages": "103-119" }, { "id": "authors:w0e6e-jdh61", "collection": "authors", "collection_id": "w0e6e-jdh61", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161108-152342060", "type": "book_section", "title": "Distributed Estimation using Bayesian Consensus Filtering", "book_title": "American Control Conference (ACC), 2014", "author": [ { "family_name": "Bandyopadhyay", "given_name": "Saptarshi", "clpid": "Bandyopadhyay-S" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "We present the Bayesian consensus filter (BCF) for tracking a moving target using a networked group of sensing agents and achieving consensus on the best estimate of the probability distributions of the target's states. Our BCF framework can incorporate nonlinear target dynamic models, heterogeneous nonlinear measurement models, non-Gaussian uncertainties, and higher-order moments of the locally estimated posterior probability distribution of the target's states obtained using Bayesian filters. If the agents combine their estimated posterior probability distributions using a logarithmic opinion pool, then the sum of Kullback\u2013Leibler divergences between the consensual probability distribution and the local posterior probability distributions is minimized. Rigorous stability and convergence results for the proposed BCF algorithm with single or multiple consensus loops are presented. Communication of probability distributions and computational methods for implementing the BCF algorithm are discussed along with a numerical example.", "doi": "10.1109/ACC.2014.6858896", "isbn": "978-1-4799-3272-6", "publisher": "IEEE", "place_of_publication": "New York, NY", "publication_date": "2014-06", "pages": "634-641" }, { "id": "authors:49evn-kr703", "collection": "authors", "collection_id": "49evn-kr703", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161123-103752838", "type": "book_section", "title": "Distance optimal target assignment in robotic networks under communication and sensing constraints", "book_title": "IEEE International Conference on Robotics and Automation (ICRA), 2014", "author": [ { "family_name": "Yu", "given_name": "Jingjin", "clpid": "Yu-Jingjin" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Voulgaris", "given_name": "Petros G.", "clpid": "Voulgaris-P-G" } ], "abstract": "We study the problem of minimizing the total distance incurred in assigning a group of mobile robots to an equal number of static targets. Assuming that the robots have limited, range-based communication and target-sensing capabilities, we present a necessary and sufficient condition for ensuring distance optimality when robots and targets are uniformly randomly distributed. We then provide an explicit, non-asymptotic formula for computing the number of robots needed for guaranteeing optimality in terms of the robots' sensing and communication capabilities with arbitrarily high probabilities. The bound given in the formula is also asymptotically tight. Due to the large number of robots needed for high-probability optimality guarantee, we continue to investigate strategies for cases in which the number of robots cannot be freely chosen. We show that a properly designed strategy can be asymptotically optimal or suboptimal with constant approximation ratios.", "doi": "10.1109/ICRA.2014.6906991", "isbn": "978-1-4799-3685-4", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2014-06", "pages": "1098-1105" }, { "id": "authors:jr1tb-f2e52", "collection": "authors", "collection_id": "jr1tb-f2e52", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161123-102301602", "type": "book_section", "title": "Traveled distance minimization and hierarchical strategies for robotic networks", "book_title": "6th International Symposium on Communications, Control and Signal Processing (ISCCSP), 2014", "author": [ { "family_name": "Yu", "given_name": "Jingjin", "clpid": "Yu-Jingjin" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Voulgaris", "given_name": "Petros G.", "clpid": "Voulgaris-P-G" } ], "abstract": "We study the distance optimal assignment of n mobile robots to an equal number of targets under communication and target-sensing constraints. Extending previous results over uniform distributions, we show that when the robots and targets assume the same but arbitrary distribution over the unit square, a carefully designed distributed hierarchical strategy has expected travel distance that matches the best known upper bound assuming global communication and infinite target-sensing range. In a sense, our result shows that for target assignment problems in robotic networks, local optimality also offers good guarantees on global optimality.", "doi": "10.1109/ISCCSP.2014.6877920", "isbn": "978-1-4799-2890-3", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2014-05", "pages": "491-496" }, { "id": "authors:h9ysw-tmq47", "collection": "authors", "collection_id": "h9ysw-tmq47", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161221-141750231", "type": "book_section", "title": "Vision-Based Localization and Mapping for an Autonomous Mower", "book_title": "2013 IEEE/RSJ International Conference on Intelligent Robots and Systems", "author": [ { "family_name": "Yang", "given_name": "Junho", "clpid": "Yang-Junho" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Hutchinson", "given_name": "Seth", "orcid": "0000-0002-3949-6061", "clpid": "Hutchinson-Seth" }, { "family_name": "Johnson", "given_name": "David", "clpid": "Johnson-David" }, { "family_name": "Kise", "given_name": "Michio", "clpid": "Kise-Michio" } ], "abstract": "This paper presents a vision-based localization and mapping algorithm for an autonomous mower. We divide the task for robotic mowing into two separate phases, a teaching phase and a mowing phase. During the teaching phase, the mower estimates the 3D positions of landmarks and defines a boundary in the lawn with an estimate of its own trajectory. During the mowing phase, the location of the mower is estimated using the landmark and boundary map acquired from the teaching phase. Of particular interest for our work is ensuring that the estimator for landmark mapping will not fail due to the nonlinearity of the system during the teaching phase. A nonlinear observer is designed with pseudo-measurements of each landmark's depth to prevent the map estimator from diverging. Simultaneously, the boundary is estimated with an EKF. Measurements taken from an omnidirectional camera, an IMU, and a ground speed sensor are used for the estimation. Numerical simulations and offline teaching phase experiments with our autonomous mower demonstrate the potential of our algorithm.", "doi": "10.1109/IROS.2013.6696878", "isbn": "978-1-4673-6358-7", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2013-11", "pages": "3655-3662" }, { "id": "authors:pj4qv-41q73", "collection": "authors", "collection_id": "pj4qv-41q73", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161123-070853922", "type": "book_section", "title": "Motion Primitives and 3-D Path Planning for Fast Flight through a Forest", "book_title": "IEEE/RSJ International Conference on Intelligent Robots and Systems, 2013", "author": [ { "family_name": "Panahandeh", "given_name": "Ghazaleh", "clpid": "Panahandeh-Ghazaleh" }, { "family_name": "Meier", "given_name": "Kevin C.", "orcid": "0000-0003-4000-1422", "clpid": "Meier-K-C" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Shi", "given_name": "Xichen", "clpid": "Shi-Xichen" }, { "family_name": "Hutchinson", "given_name": "Seth", "orcid": "0000-0002-3949-6061", "clpid": "Hutchinson-Seth" } ], "contributor": [ { "family_name": "Amato", "given_name": "N.", "clpid": "Amato-N" } ], "abstract": "This paper addresses the problem of motion planning for fast, agile flight through a dense obstacle field. A key contribution is the design of two families of motion primitives for aerial robots flying in dense obstacle fields, along with rules to stitch them together. The primitives are obtained by solving for the flight dynamics of the aerial robot, and explicitly account for limited agility using time delays. The first family of primitives consists of turning maneuvers to link any two points in space. The locations of the terminal points are used to obtain closed-form expressions for the control inputs required to fly between them, while accounting for the finite time required to switch between consecutive sets of control inputs. The second family consists of aggressive turn-around maneuvers wherein the time delay between the angle of attack and roll angle commands is used to optimize the maneuver for the spatial constraints. A 3-D motion planning algorithm based on these primitives is presented for aircraft flying through a dense forest.", "doi": "10.1109/IROS.2013.6696773", "isbn": "978-1-4673-6358-7", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2013-11", "pages": "2940-2947" }, { "id": "authors:mj4n8-bmt27", "collection": "authors", "collection_id": "mj4n8-bmt27", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161123-064941445", "type": "book_section", "title": "Image Moments for Higher-Level Feature Based Navigation", "book_title": "IEEE/RSJ International Conference on Intelligent Robots and Systems, 2013", "author": [ { "family_name": "Dani", "given_name": "Ashwin P.", "clpid": "Dani-Ashwin-P" }, { "family_name": "Panahandeh", "given_name": "Ghazaleh", "clpid": "Panahandeh-Ghazaleh" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Hutchinson", "given_name": "Seth", "orcid": "0000-0002-3949-6061", "clpid": "Hutchinson-Seth" } ], "contributor": [ { "family_name": "Amato", "given_name": "N.", "clpid": "Amato-N" } ], "abstract": "This paper presents a novel vision-based localization and mapping algorithm using image moments of region features. The environment is represented using regions, such as planes and/or 3D objects instead of only a dense set of feature points. The regions can be uniquely defined using a small number of parameters; e.g., a plane can be completely characterized by normal vector and distance to a local coordinate frame attached to the plane. The variation of image moments of the regions in successive images can be related to the parameters of the regions. Instead of tracking a large number of feature points, variations of image moments of regions can be computed by tracking the segmented regions or a few feature points on the objects in successive images. A map represented by regions can be characterized using a minimal set of parameters. The problem is formulated as a nonlinear filtering problem. A new discrete-time nonlinear filter based on the state-dependent coefficient (SDC) form of nonlinear functions is presented. It is shown via Monte-Carlo simulations that the new nonlinear filter is more accurate and consistent than EKF by evaluating the root-mean squared error (RMSE) and normalized estimation error squared (NEES).", "doi": "10.1109/IROS.2013.6696413", "isbn": "978-1-4673-6358-7", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2013-11", "pages": "602-609" }, { "id": "authors:fx429-jxr87", "collection": "authors", "collection_id": "fx429-jxr87", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161129-102652656", "type": "book_section", "title": "Optimizing the Forces and Propulsive Efficiency in Bird-Scale Flapping Flight", "author": [ { "family_name": "Paranjape", "given_name": "Aditya A.", "orcid": "0000-0002-3164-3215", "clpid": "Paranjape-A-A" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Hilton", "given_name": "Harry H.", "clpid": "Hilton-H-H" } ], "abstract": "This paper presents first-principle and numerical studies of flapping flight with the objective of optimizing the force production and propulsive effciency. Strouhal number is identified as a critical parameter affecting all of these variables, and the optimum ranges of Strouhal number are calculated. The results of the calculations, in particular, explain why a value in the range of 0.2-0.4 is usually preferred by nature's flyers. Next, an attempt is made to quantify the effects of wing flexibility on force generation and propulsive efficiency, and it is shown that there exists a critical value of wing elasticity at which propulsive efficiency is maximized, and moreover, this value is driven primarily by the dynamics of the bending\nmotion of the wing rather than twisting.", "doi": "10.2514/6.2013-4916", "publisher": "American Institute of Aeronautics and Astronautics (AIAA)", "publication_date": "2013-08" }, { "id": "authors:wncdg-75068", "collection": "authors", "collection_id": "wncdg-75068", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161130-063732477", "type": "book_section", "title": "Optimum Spatially Constrained Turns for Agile Micro Aerial Vehicles", "book_title": "AIAA Guidance, Navigation, and Control Conference", "author": [ { "family_name": "Paranjape", "given_name": "Aditya A.", "orcid": "0000-0002-3164-3215", "clpid": "Paranjape-A-A" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Hutchinson", "given_name": "Seth", "orcid": "0000-0002-3949-6061", "clpid": "Hutchinson-Seth" } ], "abstract": "The objective of this paper is to derive a rapid turn-around maneuver for micro aerial vehicles flying in densely cluttered environments, in the form of variable altitude turns optimized for spatial constraints. The design results in a motion primitive which can be\nimplemented on miniature aircraft at large. The primitive is tested on an MAV equipped with just yaw control and no roll control. The maneuver design not only yields a motion\nprimitive for a turn-around maneuver, but also sheds light on the aircraft design features that enable such a maneuver to be accomplished given some information about the obstacle\nfield.", "doi": "10.2514/6.2013-4941", "isbn": "978-1-62410-224-0", "publisher": "AIAA", "place_of_publication": "Reston, VA", "publication_date": "2013-08", "pages": "Art. No.-2013" }, { "id": "authors:4jrqb-vjq70", "collection": "authors", "collection_id": "4jrqb-vjq70", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161130-084925184", "type": "book_section", "title": "Inertial-Aided Vision-Based Localization and Mapping in a Riverine Environment with Reflection Measurements", "book_title": "AIAA Guidance, Navigation, and Control Conference 2013", "author": [ { "family_name": "Yang", "given_name": "Junho", "clpid": "Yang-Junho" }, { "family_name": "Dani", "given_name": "Ashwin P.", "clpid": "Dani-Ashwin-P" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Hutchinson", "given_name": "Seth", "orcid": "0000-0002-3949-6061", "clpid": "Hutchinson-Seth" } ], "abstract": "This paper presents an inertial-aided vision-based localization and mapping algorithm for an unmanned aerial vehicle (UAV) that can operate in a GPS-denied riverine environment. We take vision measurements from the features surrounding the river and their corresponding points reflected in the river. We apply a robot-centric mapping framework to let the uncertainty of the features be referenced to the UAV body frame and estimate the 3D positions of point features while estimating the location of the UAV. We demonstrate the localization and mapping results with sensors on our quadcopter UAV platform\nin the University of Illinois at Urbana Champaign Boneyard Creek. The UAV is equipped with a light weight monocular camera, an inertial measurement unit (IMU) which contains\na magnetometer, an ultrasound altimeter, and an on-board computer. To our knowledge, we report the first result of performing localization and mapping by exploiting multiple\nviews with reflections of features in a river-like environment.", "doi": "10.2514/6.2013-5246", "isbn": "978-1-62410-224-0", "publisher": "American Institute of Aeronautics and Astronautics (AIAA)", "place_of_publication": "Boston MA", "publication_date": "2013-08", "pages": "Art. No.-2013" }, { "id": "authors:f311v-tpx84", "collection": "authors", "collection_id": "f311v-tpx84", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161222-070302558", "type": "book_section", "title": "Decentralized Model Predictive Control of Swarms of Spacecraft Using Sequential Convex Programming", "book_title": "Spaceflight mechanics meeting, 2013", "author": [ { "family_name": "Morgan", "given_name": "Daniel", "clpid": "Morgan-Daniel" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Hadaegh", "given_name": "Fred Y.", "clpid": "Hadaegh-F-Y" } ], "abstract": "This paper presents a decentralized, model predictive control algorithm for the reconfiguration of swarms of spacecraft composed of hundreds to thousands of agents with limited capabilities. In our prior work, sequential convex programming has been used to determine collision-free, fuel-efficient trajectories for the reconfiguration of spacecraft swarms. This paper uses a model predictive control approach to implement the sequential convex programming algorithm in real-time. By updating the optimal trajectories during the reconfiguration, the model predictive control algorithm results in decentralized computations and communication between neighboring spacecraft only. Additionally, model predictive control reduces the horizon of the convex optimizations, which reduces the run time of the algorithm.", "isbn": "978-0-87703-597-8", "publisher": "Univelt Inc.", "publication_date": "2013-02", "pages": "1-20" }, { "id": "authors:bfbgg-tmr10", "collection": "authors", "collection_id": "bfbgg-tmr10", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161109-083117350", "type": "book_section", "title": "Observer Design for Stochastic Nonlinear Systems using Contraction Analysis", "book_title": "2012 IEEE 51st IEEE Conference on Decision and Control (CDC)", "author": [ { "family_name": "Dani", "given_name": "Ashwin P.", "clpid": "Dani-Ashwin-P" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Hutchinson", "given_name": "Seth", "orcid": "0000-0002-3949-6061", "clpid": "Hutchinson-Seth" } ], "abstract": "This paper presents a new observer for It\u00f4 stochastic nonlinear systems with guaranteed stability. Contraction analysis is used to analyze incremental stability of the observer for an It\u00f4 stochastic nonlinear system. A bound on the mean squared distance between the trajectories of original dynamics and the observer dynamics is obtained as a function of contraction rate and maximum noise intensity. The observer design is based on non-unique state-dependent coefficient (SDC) forms which parametrize the nonlinearity in an extended linear form. In this paper, a convex combination of several parametrizations is used. An optimization problem with state-dependent linear matrix inequality (SDLMI) constraints is formulated to select the free parameters of the convex combination for achieving faster convergence and robustness against disturbances. Moreover, the L_2 norm of the disturbance and noise to the estimation error is shown to be finite. The present algorithm shows improved performance in comparison to the extended Kalman filter (EKF) and the state-dependent differential Riccati equation (SDDRE) filter in simulation.", "doi": "10.1109/CDC.2012.6425977", "isbn": "978-1-4673-2066-5", "publisher": "IEEE", "place_of_publication": "New York, NY", "publication_date": "2012-12", "pages": "6028-6035" }, { "id": "authors:9bghm-w1d64", "collection": "authors", "collection_id": "9bghm-w1d64", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161109-084215066", "type": "book_section", "title": "PDE Boundary Control for Euler-Bernoulli Beam Using a Two Stage Perturbation Observer", "book_title": "51st IEEE Conference on Decision and Control (CDC)", "author": [ { "family_name": "Paranjape", "given_name": "Aditya A.", "orcid": "0000-0002-3164-3215", "clpid": "Paranjape-A-A" }, { "family_name": "Guan", "given_name": "Jinyu", "clpid": "Guan-Jinyu" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Krstic", "given_name": "Miroslav", "clpid": "Krstic-Miroslav" } ], "abstract": "A novel perturbation observer-based PDE boundary control law for beam bending is derived based on a combination of perturbation observers and polynomial trajectory planning. The perturbation observer consists of two components. The first stage employs the \"particular\" solution of the original dynamics with disturbances while its boundary conditions are set to zero. In contrast, the dynamics of the \"homogeneous component\" are independent of the beam dynamics, but its boundary conditions are identical to those of the beam. A tracking boundary control law, based on trajectory planning, is designed for the homogeneous component, and the same control signal is also applied to the beam. The stability of the adaptive perturbation-observer is proven by Lyapunov stability in the spatial L2 sense, while stability conditions are derived for a finite dimensional ODE analogue of the infinite dimensional closed loop PDE system. This paper also reports on one of the first experimental demonstrations of a controller designed entirely using a PDE boundary control formulation.", "doi": "10.1109/CDC.2012.6426058", "isbn": "978-1-4673-2066-5", "publisher": "IEEE", "place_of_publication": "New York, NY", "publication_date": "2012-12", "pages": "4442-4448" }, { "id": "authors:s3r1v-tpr82", "collection": "authors", "collection_id": "s3r1v-tpr82", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161109-082124457", "type": "book_section", "title": "CurveSLAM: An approach for vision-based navigation without point features", "book_title": "2012 IEEE/RSJ International Conference on Intelligent Robots and Systems", "author": [ { "family_name": "Rao", "given_name": "Dushyant", "clpid": "Rao-Dushyant" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Hutchinson", "given_name": "Seth", "orcid": "0000-0002-3949-6061", "clpid": "Hutchinson-Seth" } ], "abstract": "Existing approaches to visual Simultaneous Localization and Mapping (SLAM) typically utilize points as visual feature primitives to represent landmarks in the environment. Since these techniques mostly use image points from a standard feature point detector, they do not explicitly map objects or regions of interest. Our work is motivated by the need for different SLAM techniques in path and riverine settings, where feature points can be scarce or may not adequately represent the environment. Accordingly, the proposed approach uses cubic B\u00e9zier curves as stereo vision primitives and offers a novel SLAM formulation to update the curve parameters and vehicle pose. This method eliminates the need for point-based stereo matching, with an optimization procedure to directly extract the curve information in the world frame from noisy edge measurements. Further, the proposed algorithm enables navigation with fewer feature states than most point-based techniques, and is able to produce a map which only provides detail in key areas. Results in simulation and with vision data validate that the proposed method can be effective in estimating the 6DOF pose of the stereo camera, and can produce structured, uncluttered maps.", "doi": "10.1109/IROS.2012.6385764", "isbn": "978-1-4673-1736-8", "publisher": "IEEE", "place_of_publication": "New York, NY", "publication_date": "2012-10", "pages": "4198-4204" }, { "id": "authors:2naye-vf695", "collection": "authors", "collection_id": "2naye-vf695", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161129-114235228", "type": "book_section", "title": "Closed-Loop Perching and Spatial Guidance Laws for Bio-Inspired Articulated Wing MAV", "book_title": "AIAA Guidance, Navigation, and Control Conference, 2012", "author": [ { "family_name": "Paranjape", "given_name": "Aditya", "orcid": "0000-0002-3164-3215", "clpid": "Paranjape-A-A" }, { "family_name": "Kim", "given_name": "Joseph", "clpid": "Kim-Joseph" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "This paper presents the underlying theoretical developments and successful experimental demonstrations of perching of an aerial robot. The open-loop lateral-directional dynamics of the robot are inherently unstable because it lacks a vertical tail for agility, similar to birds. A unique feature of this robot is that it uses wing articulation for controlling the flight path angle as well as the heading. New guidance algorithms with guaranteed stability are obtained by rewriting the flight dynamic equations in the spatial domain rather than as functions of time, after which dynamic inversion is employed. It is shown that nonlinear dynamic inversion naturally leads to proportional-integral-derivative (PID) controllers, thereby providing an exact method for tuning the gains. The effectiveness of the proposed bio-inspired robot design and its novel closed-loop perching controller has been successfully demonstrated with perched landings on a human hand.", "doi": "10.2514/6.2012-4979", "isbn": "978-1-60086-938-9", "publisher": "AIAA", "place_of_publication": "Reston, VA", "publication_date": "2012-08", "pages": "Art. No.-2012" }, { "id": "authors:s9met-t5977", "collection": "authors", "collection_id": "s9met-t5977", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161222-111933253", "type": "book_section", "title": "Spacecraft Swarm Guidance Using a Sequence of Decentralized Convex Optimizations", "book_title": "AIAA/AAS Astrodynamics Specialist Conference", "author": [ { "family_name": "Morgan", "given_name": "Daniel", "clpid": "Morgan-Daniel" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Hadaegh", "given_name": "Fred", "clpid": "Hadaegh-F-Y" } ], "abstract": "This paper presents partially decentralized path planning algorithms for swarms of spacecraft composed of hundreds to thousands of agents with each spacecraft having limited computational capabilities. In our prior work, J2-invariant orbits have been found to provide collision free motion for hundreds of orbits. This paper develops algorithms for the\nswarm reconfiguration which involves transferring from one J2-invariant orbit to another avoiding collisions and minimizing fuel. To perform collision avoidance, it is assumed that the spacecraft can communicate their trajectories with each other. The algorithm uses\nsequential convex programming to solve a series of approximate path planning problems until the solution converges. Two decentralized methods are developed: a serial method where the spacecraft take turn updating their trajectories and a parallel method where all of the spacecraft update their trajectories simultaneously.", "doi": "10.2514/6.2012-4583", "isbn": "978-1-62410-182-3", "publisher": "American Institute of Aeronautics and Astronautics", "place_of_publication": "Reston, VA", "publication_date": "2012-08", "pages": "Art. No. 2012-4583" }, { "id": "authors:mkyh2-73153", "collection": "authors", "collection_id": "mkyh2-73153", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161109-080512793", "type": "book_section", "title": "Fabrication and analysis of planar dielectric elastomer actuators capable of complex 3-D deformation", "book_title": "2012 IEEE International Conference on Robotics and Automation", "author": [ { "family_name": "Lai", "given_name": "William", "clpid": "Lai-William" }, { "family_name": "Bastawros", "given_name": "Ashraf F.", "clpid": "Bastawros-A-F" }, { "family_name": "Hong", "given_name": "Wei", "clpid": "Hong-Wei" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "A new design for a dielectric elastomer actuator with geometrically confining reinforcements is presented. The resulting structures enable complex 3-dimentional motion without the need of the membrane prestretch. An in situ imaging system is used to capture the complex deformation pattern to evaluate the surface curvatures. The deformation mode is analyzed analytically using the bi-laminate theory to explore the actuator performance and further develop analytical model amenable for control strategies. A finite element material model is also developed to couple the applied electric field to the resulting deformation. The model is used to analyze more complex deformation patterns. The proposed confining reinforcements would enable the development of flexible wings for agile aerial robotics and compliant continuum robotics, utilizing the proposed deformation mechanisms to provide controllable many degrees of freedom.", "doi": "10.1109/ICRA.2012.6225079", "isbn": "978-1-4673-1405-3", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2012-05", "pages": "4968-4973" }, { "id": "authors:vf97z-nkj94", "collection": "authors", "collection_id": "vf97z-nkj94", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161130-094235795", "type": "book_section", "title": "Towards Bio-Inspired Robotic Aircraft: Control Experiments on Flapping and Gliding Flight", "book_title": "Advances in Intelligent and Autonomous Aerospace Systems", "author": [ { "family_name": "Dorothy", "given_name": "Michael", "clpid": "Dorothy-M-R" }, { "family_name": "Paranjape", "given_name": "Aditya A.", "orcid": "0000-0002-3164-3215", "clpid": "Paranjape-A-A" }, { "family_name": "Kuang", "given_name": "P. Daniel", "clpid": "Kuang-P-Daniel" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "contributor": [ { "family_name": "Valasek", "given_name": "John", "clpid": "Valasek-J" } ], "abstract": "THERE is a growing interest in the aerospace community in the development of robotic micro aerial vehicles (MAVs) to learn and mimic avian flight. MAVs fly in low-Reynolds-number regimes of 103 to 105, which corresponds to that of small birds or bats [1]. MAVs with wings equipped with multiple degrees of freedom such as flapping, wing twist, and sweep provide greater payload capability than insect-like MAVs and greater maneuverability than conventional fixed-wing aircraft. These MAVs can be used for intelligence gathering, surveillence, and reconnaissance\nmissions in tightly constrained spaces such as forests and urban areas. Advances in actuators and control systems have led to development and analysis of articulated and flapping MAVs inspired by animals [2\u20135]. Birds and bats achieve remarkable stability and perform agile manuevers using their wings very effectively [2]. One of the goals of reverse-engineering animal flight is to learn more about the various aspects of avian flight such as stability, maneuverability, and control from the dynamics of MAV.", "doi": "10.2514/5.9781600868962.0001.0032", "isbn": "978-1-60086-897-9", "publisher": "American Institute of Aeronautics and Astronautics (AIAA)", "place_of_publication": "Reston, VA", "publication_date": "2012", "pages": "1-31" }, { "id": "authors:w8pww-yh795", "collection": "authors", "collection_id": "w8pww-yh795", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161222-132209268", "type": "book_section", "title": "Experimental Demonstration of Perching by an Articulated Wing MAV", "book_title": "AIAA Guidance, Navigation, and Control Conference 2011", "author": [ { "family_name": "Paranjape", "given_name": "Aditya", "orcid": "0000-0002-3164-3215", "clpid": "Paranjape-A-A" }, { "family_name": "Kim", "given_name": "Joseph", "clpid": "Kim-Joseph" }, { "family_name": "Gandhi", "given_name": "Nihar", "clpid": "Gandhi-Nihar" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "This paper presents an experimental demonstration of perching by a micro aerial vehicle (MAV) equipped with articulated wings. A novel feature of the MAV considered in\nthis paper is that wing dihedral, controlled independently on both wings, is used for yaw stability and control as well as for maintaining the flight path angle. Yaw stability and control are essential for perching in tightly constrained places. The experiments described in this paper were conducted indoors and flight parameters are measured using the VICON motion capture system.", "doi": "10.2514/6.2011-6403", "isbn": "978-1-60086-952-5", "publisher": "American Institute of Aeronautics and Astronautics", "place_of_publication": "Reston, VA", "publication_date": "2011-08", "pages": "Art. No. 2011-6403" }, { "id": "authors:fg4mg-3px53", "collection": "authors", "collection_id": "fg4mg-3px53", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161222-113047812", "type": "book_section", "title": "Swarm Keeping Strategies for Spacecraft under J_2 and Atmospheric Drag Perturbations", "book_title": "AIAA Guidance, Navigation, and Control Conference 2011", "author": [ { "family_name": "Morgan", "given_name": "Daniel", "clpid": "Morgan-Daniel" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Blackmore", "given_name": "Lars", "clpid": "Blackmore-L" }, { "family_name": "Acikmese", "given_name": "Behcet", "clpid": "Acikmese-B" }, { "family_name": "Bayard", "given_name": "David S.", "clpid": "Bayard-D-S" }, { "family_name": "Hadaegh", "given_name": "Fred Y.", "clpid": "Hadaegh-F-Y" } ], "abstract": "This paper presents several new open-loop guidance methods for spacecraft swarms composed of hundreds to thousands of agents with each spacecraft having modest capabilities. These methods have three main goals: preventing relative drift of the swarm, preventing collisions within the swarm, and minimizing the propellant used throughout the mission. The development of these methods progresses by eliminating drift using the Hill-Clohessy-Wiltshire equations, removing drift due to nonlinearity, and minimizing the J_2 drift. In order to verify these guidance methods, a new dynamic model for the relative motion of spacecraft is developed. These dynamics include the two main disturbances for spacecraft in Low Earth Orbit (LEO), J_2 and atmospheric drag. Using this dynamic model, numerical simulations are provided at each step to show the effectiveness of each method and to see where improvements can be made. The main result is a set of initial conditions for each spacecraft in the swarm which provides the trajectories for hundreds of collision-free orbits in the presence of J_2. Finally, a multi-burn strategy is developed in order to provide hundreds of collision-free orbits under the influence of atmospheric drag. This last method works by enforcing the initial conditions multiple times throughout the mission thereby providing collision-free trajectories for the duration of the mission.", "doi": "10.2514/6.2011-6632", "isbn": "978-1-60086-952-5", "publisher": "American Institute of Aeronautics and Astronautics (AIAA)", "place_of_publication": "Reston, VA", "publication_date": "2011-08", "pages": "Art. No. 2011-6632" }, { "id": "authors:yhp1a-bzy61", "collection": "authors", "collection_id": "yhp1a-bzy61", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161130-081544822", "type": "book_section", "title": "Phase Synchronization Control of Robotic Networks on Periodic Ellipses with Adaptive Network Topologies", "book_title": "AIAA Guidance, Navigation, and Control Conference 2011", "author": [ { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Chang", "given_name": "Insu", "clpid": "Chang-Insu" }, { "family_name": "Hadaegh", "given_name": "Fred Y.", "orcid": "0000-0002-0992-6323", "clpid": "Hadaegh-F-Y" } ], "abstract": "This paper presents a novel formation control method for a large number of robots or vehicles described by Euler-Lagrange (EL) systems moving in elliptical orbits. A new\ncoordinate transformation method for phase synchronization of networked EL systems in elliptical trajectories is introduced to define desired formation patterns. The proposed phase synchronization controller synchronizes the motions of agents, thereby yielding a smaller synchronization error than an uncoupled control law in the presence of bounded disturbances. A complex time-varying and switching network topology, constructed by the\nadaptive graph Laplacian matrix, relaxes the standard requirement of consensus stability, even permitting stabilization on an arbitrary unbalanced graph. The proofs of stability are constructed by robust contraction analysis, a relatively new nonlinear stability tool. An\nexample of reconfiguring swarms of spacecraft in Low Earth Orbit shows the effectiveness of the proposed phase synchronization controller for a large number of complex EL systems moving in elliptical orbits.", "doi": "10.2514/6.2011-6631", "isbn": "978-1-60086-952-5", "publisher": "American Institute of Aeronautics and Astronautics (AIAA)", "place_of_publication": "Reston, VA", "publication_date": "2011-08", "pages": "1-19" }, { "id": "authors:rc0fc-gce77", "collection": "authors", "collection_id": "rc0fc-gce77", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161222-122638313", "type": "book_section", "title": "PDE Boundary Control for Flexible Articulated Aircraft Wings", "book_title": "AIAA Guidance, Navigation, and Control Conference 2011", "author": [ { "family_name": "Paranjape", "given_name": "Aditya A.", "orcid": "0000-0002-3164-3215", "clpid": "Paranjape-A-A" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Krstic", "given_name": "Miroslav", "clpid": "Krstic-Miroslav" } ], "abstract": "The paper considers a boundary control formulation for PDEs with a system output given by a spatial integral of weighted functions of the state. This formulation is directly applicable to the control of an aircraft with articulated exible wings, in which case the output of interest is a net aerodynamic force or moment. Flexible wings can be controlled via actuation at the root or the tip. The problem of beam twist is analysed in detail to\nillustrate the formulation, and it shown that the control law ensures that the error between the desired output signal and the actual output signal decreases exponentially to an uniform ultimate bound. Stability of the closed loop system is proved by Lyapunov techniques. The formulation is demonstrated by simulations.", "doi": "10.2514/6.2011-6486", "isbn": "978-1-60086-952-5", "publisher": "American Institute of Aeronautics and Astronautics (AIAA)", "place_of_publication": "Reston, VA", "publication_date": "2011-08", "pages": "Art. No. 2011-6486" }, { "id": "authors:qqbmb-j8z50", "collection": "authors", "collection_id": "qqbmb-j8z50", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161201-072209482", "type": "book_section", "title": "Novel Coordinate Transformation and Robust Cooperative Formation Control for Swarms of Spacecraft", "author": [ { "family_name": "Chang", "given_name": "Insu", "clpid": "Chang-Insu" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Hadaegh", "given_name": "Fred Y.", "clpid": "Hadaegh-F-Y" } ], "abstract": "This paper presents a new coordinate transformation method for controlling a large number of spacecraft moving in elliptical orbits. A new coordinate transformation\nmethod for phase synchronization of spacecraft in relative elliptical orbits is introduced to effectively maintain desired formation patterns. The proposed controller, which\nemploys both the adaptive graph Laplacian matrix and the distance-based connectivity rule, synchronizes the relative motions of spacecraft with a guaranteed property of\nrobustness. A complex time-varying network topology, constructed by the proposed controller, relaxes the standard requirement of consensus stability, even permitting\nstabilization on an arbitrary unbalanced graph. A challenging example of reconfiguring swarms of spacecraft shows the reliability of the coordinate transformation method and the effectiveness of the proposed phase synchronization controller.", "publisher": "Caltech Library", "publication_date": "2011-05" }, { "id": "authors:e5dr9-w8422", "collection": "authors", "collection_id": "e5dr9-w8422", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170120-140152107", "type": "book_section", "title": "An Evolutionary Architecture for the Automated Conceptual Design of Aerospace Systems", "book_title": "AIAA Infotech at Aerospace Conference and Exhibit 2011", "author": [ { "family_name": "Duffy", "given_name": "Michael", "clpid": "Duffy-M" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Bergman", "given_name": "Lawrence", "clpid": "Bergman-L" } ], "abstract": "Many different approaches to total system design and optimization have been atempted. The Genetic Learning Automated Design Optimization Software (GLADOS) presented here represent a flexible evolutionary algorithm bases architecture intented to allow for the generation of conceptual or preliminary design stage aircraft designs without any human beings in the loop. The benefits of this approach being more thorough exploration of the design space, the ability to analyze and produce high commonality and modular and modular design configurations, and allowing design capabilities to directly growing computational capabilities. Both an overview of the idealized architecture as well as the results from a simplified test version are presented.", "doi": "10.2514/6.2011-1632", "isbn": "9781617829741", "publisher": "American Institute of Aeronautics and Astronautics", "place_of_publication": "Reston", "publication_date": "2011-03" }, { "id": "authors:7yc73-5c258", "collection": "authors", "collection_id": "7yc73-5c258", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161221-134632205", "type": "book_section", "title": "RoboBat: Dynamics and Control of a Robotic Bat Flapping Flying Testbed", "book_title": "Infotech@Aerospace 2011", "author": [ { "family_name": "Fong", "given_name": "Daniel", "clpid": "Fong-Daniel" }, { "family_name": "Dorothy", "given_name": "Michael", "clpid": "Dorothy-M-R" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "This paper investigates the control of the phase difference in between three different motions of bat flight: pitching, mapping, and lead-lag. For active control, a robotic bat test bed capable of simulating different wing motions is used to test the control of these wing motions and the phase differences using central pattern generators (CPG's). Previous work with the robotic bat is expanded upon by modifying the robotic bat test bed to allow for three dimensional motions of the entire bat, instead of only the wings. This is done by mounting the robotic bat onto a 3D pendulum. Experiments analyzing the steady state behavior of the bat's flight with varying phase differences showed a change of pitch while elevation and forward velocity remains constant. This shows promising results regarding the relation between phase differences of wing motions and longitudinal stability.", "doi": "10.2514/6.2011-1435", "isbn": "978-1-60086-944-0", "publisher": "American Institute of Aeronautics and Astronautics (AIAA)", "place_of_publication": "Reston, VA", "publication_date": "2011-03", "pages": "Art. No. 2011-1435" }, { "id": "authors:k3yfh-rd485", "collection": "authors", "collection_id": "k3yfh-rd485", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161130-135343959", "type": "book_section", "title": "Monocular Vision based Navigation in GPS-Denied Riverine Environments", "book_title": "Infotech@Aerospace Conference and Exhibit 2011", "author": [ { "family_name": "Yang", "given_name": "Junho", "clpid": "Yang-Junho" }, { "family_name": "Rao", "given_name": "Dushyant", "clpid": "Rao-Dushyant" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Hutchinson", "given_name": "Seth", "orcid": "0000-0002-3949-6061", "clpid": "Hutchinson-Seth" } ], "abstract": "This paper presents a new method to estimate the range and bearing of landmarks and solve the simultaneous localization and mapping (SLAM) problem. The proposed\nranging and SLAM algorithms have application to a micro aerial vehicle (MAV) flying through riverine environments which occasionally involve heavy foliage and forest canopy.\nMonocular vision navigation has merits in MAV applications since it is lightweight and provides abundant visual cues of the environment in comparison to other ranging methods.\nIn this paper, we suggest a monocular vision strategy incorporating image segmentation and epipolar geometry to extend the capability of the ranging method to unknown outdoor environments. The validity of our proposed method is verified through experiments in a river-like environment.", "doi": "10.2514/6.2011-1403", "isbn": "978-1-60086-944-0", "publisher": "American Institute of Aeronautics and Astronautics (AIAA)", "place_of_publication": "Reston, VA", "publication_date": "2011-03", "pages": "Art. No. 2011-1403" }, { "id": "authors:x15gc-qtw84", "collection": "authors", "collection_id": "x15gc-qtw84", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161109-075145395", "type": "book_section", "title": "On synchronization of coupled Hopf-Kuramoto oscillators with phase delays", "book_title": "49th IEEE Conference on Decision and Control (CDC)", "author": [ { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Slotine", "given_name": "Jean-Jacques", "clpid": "Slotine-J-J-E" } ], "abstract": "This paper presents new methods and results on synchronization of coupled Hopf nonlinear oscillators, which are commonly used as the dynamic model of engineered central pattern generators (CPGs). On balanced graphs, any positive coupling gain is proven to induce almost global asymptotic synchronization, and a threshold value for truly global exponential synchronization is also computed. Furthermore, a hierarchical connection between coupled Hopf oscillators and Kuramoto oscillators is identified. Finally, a new result on the synchronization of Kuramoto oscillators with arbitrary time-varying heterogeneous frequencies and delays is derived.", "doi": "10.1109/CDC.2010.5717962", "isbn": "978-1-4244-7746-3", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2010-12", "pages": "3181-3187" }, { "id": "authors:a3rww-4tk22", "collection": "authors", "collection_id": "a3rww-4tk22", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161201-084722017", "type": "book_section", "title": "Cooperative Control with Adaptive Graph Laplacians for Spacecraft Formation Flying", "book_title": "49th IEEE Conference on Decision and Control (CDC)", "author": [ { "family_name": "Chang", "given_name": "Insu", "clpid": "Chang-Insu" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Blackmore", "given_name": "Lars", "clpid": "Blackmore-L" } ], "abstract": "This paper investigates exact nonlinear dynamics and cooperative control for spacecraft formation flying with Earth oblateness (J2 perturbation) and atmospheric drag effects. The nonlinear dynamics for chief and deputy motions are derived by using Gauss' variational equation and the Euler-Lagrangian formulation, respectively. The proposed cooperative control employs adaptive time-varying Laplacian gains. The tracking and diffusive coupling gains are adapted by the synchronization/tracking errors and distance-based connectivity, thereby defining a time-varying network topology. Moreover, the proposed method relaxes the network structure requirement and permits an unbalanced graph. Nonlinear stability is proven by contraction analysis and incremental input-to-state stability. Numerical examples show the effectiveness of the proposed method.", "doi": "10.1109/CDC.2010.5717516", "isbn": "978-1-4244-7746-3", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2010-12", "pages": "4926-4933" }, { "id": "authors:vheg5-rce13", "collection": "authors", "collection_id": "vheg5-rce13", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161220-152114592", "type": "book_section", "title": "Methodological Remarks on CPG-Based Control of Flapping Flight", "book_title": "AIAA Atmospheric Flight Mechanics Conference", "author": [ { "family_name": "Dorothy", "given_name": "Michael", "clpid": "Dorothy-M-R" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "This paper is a companion to Chung and explores the applications of neurobiologically inspired control systems in the form of Central Pattern Generators (CPG) to control\nflapping flight dynamics. We introduce two-layer CPGs to mimic current hypotheses of mammalian studies. It is shown that symmetry breaking to initiate and recover from a turning maneuver is an effective control strategy. Attempts at dissociating slow dynamics are shown and preliminary comparisons of wing motions between biological fliers and\nartificial CPG networks are made.", "doi": "10.2514/6.2010-7634", "isbn": "978-1-62410-151-9", "publisher": "American Institute of Aeronautics and Astronautics", "place_of_publication": "Reston, VA", "publication_date": "2010-08", "pages": "Art. No.-2010" }, { "id": "authors:ex89c-yph27", "collection": "authors", "collection_id": "ex89c-yph27", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161222-121459009", "type": "book_section", "title": "Performance and Stability of an Agile Tail-less MAV with Flexible Articulated Wings", "book_title": "AIAA Atmospheric Flight Mechanics Conference 2010", "author": [ { "family_name": "Paranjape", "given_name": "Aditya", "orcid": "0000-0002-3164-3215", "clpid": "Paranjape-A-A" }, { "family_name": "Chakravarthy", "given_name": "Animesh", "clpid": "Chakravarthy-A" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Hilton", "given_name": "Harry H.", "clpid": "Hilton-H-H" } ], "abstract": "This paper considers the problems of (a) modelling the \night mechanics of a tail-less MAV equipped with \nexible articulated wings, and (b) the analysis of its turning performance. The wings are assumed to have two degrees of freedom - heave and twist. They are\nassumed to be actuated from the root, which is the abstraction of an experimental control mechanism being developed by the authors. The dihedral and twist angles at the wing root are controlled. A novel actuator concept of axial tension to control wing stiffness has been\nexplored in this paper. It is shown that axial tension in the wing has a significant effect on the turning performance of the aircraft, although the effect is not uniformly beneficial in nature. The effect of \nexibility on the steady state turning performance of the aircraft has been demonstrated by comparing it with that of a rigid aircraft, and with that of a similar aircraft possessing a wing with different elastic properties.", "doi": "10.2514/6.2010-7937", "isbn": "978-1-62410-151-9", "publisher": "American Institute of Aeronautics and Astronautics", "place_of_publication": "Reston, VA", "publication_date": "2010-08", "pages": "Art. No. 2010-7937" }, { "id": "authors:yw6tp-dxx12", "collection": "authors", "collection_id": "yw6tp-dxx12", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161221-084856591", "type": "book_section", "title": "Control Law Design for Perching an Agile MAV with Articulated Wings", "book_title": "AIAA Atmospheric Flight Mechanics Conference", "author": [ { "family_name": "Chakravarthy", "given_name": "Animesh", "clpid": "Chakravarthy-A" }, { "family_name": "Paranjape", "given_name": "Aditya", "orcid": "0000-0002-3164-3215", "clpid": "Paranjape-A-A" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "This paper explores the use of variable wing dihedral and variable wing twist (in conjunction\nwith a conventional horizontal elevator) to control an aircraft performing a perching\nmaneuver. A choice of controller architecture wherein the dihedral is employed in the\nforward path and the elevator and twist are employed in the feedback path, is considered.\nThe aircraft is modeled as a multivariable linear time-varying system. A specific perching\ntrajectory is considered; and the open-loop aircraft is longitudinally unstable for a segment\nof this perching trajectory and lateral-directionally unstable for the entire perching trajectory.\nA multivariable time-varying controller is designed to efficiently stabilize the aircraft\nas well as reject longitudinal-lateral-directional wind disturbances, while closely tracking\nthe reference perching trajectory.", "doi": "10.2514/6.2010-7934", "isbn": "978-1-62410-151-9", "publisher": "American Institute of Aeronautics and Astronautics (AIAA)", "place_of_publication": "Reston, VA", "publication_date": "2010-08", "pages": "Art. No. 2010-7934" }, { "id": "authors:9c5jr-hvq32", "collection": "authors", "collection_id": "9c5jr-hvq32", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161220-153007449", "type": "book_section", "title": "Flight Mechanics of a Tail-less Articulated Wing Aircraft", "book_title": "AIAA Atmospheric Flight Mechanics Conference", "author": [ { "family_name": "Paranjape", "given_name": "Aditya A.", "orcid": "0000-0002-3164-3215", "clpid": "Paranjape-A-A" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "This paper explores the flight mechanics of a Micro Aerial Vehicle (MAV) without a vertical tail. The key to stability and control of such an aircraft lies in the ability to control the twist and dihedral angles of both wings independently. Specifically, asymmetric dihedral can be used to control yaw whereas antisymmetric twist can be used to control roll. It has been demonstrated that wing dihedral angles can regulate sideslip and speed during a turn maneuver. The role of wing dihedral in the aircraft's longitudinal performance has been explored. It has been shown that dihedral angle can be varied symmetrically to achieve limited control over aircraft speed even as the angle of attack and flight path angle are varied. A rapid descent and perching maneuver has been used to illustrate the longitudinal agility of the aircraft. This paper lays part of the foundation for the design and stability analysis of an agile flapping wing aircraft capable of performing rapid maneuvers while gliding in a constrained environment.", "doi": "10.2514/6.2010-7633", "isbn": "978-1-62410-151-9", "publisher": "American Institute of Aeronautics and Astronautics (AIAA)", "place_of_publication": "Reston, VA", "publication_date": "2010-08", "pages": "Art. No. 2010-7633" }, { "id": "authors:1hemk-8hq81", "collection": "authors", "collection_id": "1hemk-8hq81", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161122-145958877", "type": "book_section", "title": "Exponential Stability Region Estimates for the State-Dependent Riccati Equation Controllers", "book_title": "Joint 48h IEEE Conference on Decision and Control (CDC) held jointly with 2009 28th Chinese Control Conference", "author": [ { "family_name": "Chang", "given_name": "Insu", "clpid": "Chang-Insu" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "We investigate the nonlinear exponential stability of the State-Dependent Riccati Equation (SDRE)-based control. The SDRE technique is a nonlinear control method, which has emerged since the mid 1990's and has been applied to a wide range of nonlinear control problems. Despite the systematic method of SDRE, it is difficult to prove stability because the general analytic solution to the SDRE is not known. Some notable prior work has shown local asymptotic stability of SDRE by using numerical and analytical methods. In this paper, we introduce a new strategy, based on contraction analysis, to estimate the exponential stability region for SDRE controlled systems. Examples demonstrate the superiority of the proposed method.", "doi": "10.1109/CDC.2009.5400575", "isbn": "978-1-4244-3872-3", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2009-12", "pages": "1974-1979" }, { "id": "authors:8zpg2-m1v36", "collection": "authors", "collection_id": "8zpg2-m1v36", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161122-144014712", "type": "book_section", "title": "Monocular Vision SLAM for Indoor Aerial Vehicles", "book_title": "IEEE/RSJ International Conference on Intelligent Robots and Systems, 2009", "author": [ { "family_name": "\u00c7elik", "given_name": "Koray", "clpid": "\u00c7elik-K" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Clausman", "given_name": "Matthew", "clpid": "Clausman-M" }, { "family_name": "Somani", "given_name": "Arun K.", "clpid": "Somani-A-K" } ], "abstract": "This paper presents a novel indoor navigation and ranging strategy by using a monocular camera. The proposed algorithms are integrated with simultaneous localization and mapping (SLAM) with a focus on indoor aerial vehicle applications. We experimentally validate the proposed algorithms by using a fully self-contained micro aerial vehicle (MAV) with on-board image processing and SLAM capabilities. The range measurement strategy is inspired by the key adaptive mechanisms for depth perception and pattern recognition found in humans and intelligent animals. The navigation strategy assumes an unknown, GPS-denied environment, which is representable via corner-like feature points and straight architectural lines. Experimental results show that the system is only limited by the capabilities of the camera and the availability of good corners.", "doi": "10.1109/IROS.2009.5354050", "isbn": "978-1-4244-3803-7", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2009-10", "pages": "1566-1573" }, { "id": "authors:r0js4-jrp37", "collection": "authors", "collection_id": "r0js4-jrp37", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161201-065326671", "type": "book_section", "title": "Bio-Inspired Adaptive Cooperative Control of Heterogeneous Robotic Networks", "book_title": "AIAA Guidance, Navigation, and Control Conference 2009", "author": [ { "family_name": "Chang", "given_name": "Insu", "clpid": "Chang-Insu" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "We introduce a new adaptive cooperative control strategy for robotic networks comprised of heterogeneous members. The proposed feedback synchronization exploits an active parameter adaptation strategy as opposed to adaptive parameter estimation of adaptive control theory. Multiple heterogeneous robots or vehicles can coordinate their motions by parameter adaptation analogous to bio-genetic mutation and adaptation. In contrast with fixed gains used by consensus theory, both the tracking control and diffusive coupling gains are automatically computed based on the adaptation law, the synchronization errors, and the tracking errors of heterogeneous robots. The optimality of the proposed adaptive cooperative control is studied via inverse optimal control theory. The proposed adaptive\ncooperative control can be applied to any network structure. The stability proof, by using a relatively new nonlinear stability tool, contraction theory, shows globally asymptotically synchronized motion of a heterogeneous robotic network. This adaptive cooperative control can be widely applied to cooperative control of unmanned aerial vehicles (UAVs), formation flying spacecraft, and multi-robot systems. Results of the simulation show the effectiveness of the proposed adaptive cooperative control laws especially for a network comprised of heterogeneous members.", "doi": "10.2514/6.2009-5886", "isbn": "978-1-60086-978-5", "publisher": "American Institute of Aeronautics and Astronautics (AIAA)", "place_of_publication": "Reston, VA", "publication_date": "2009-08", "pages": "Art. No. 2009-5886" }, { "id": "authors:ga8c4-ggq46", "collection": "authors", "collection_id": "ga8c4-ggq46", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161221-071846444", "type": "book_section", "title": "Neurobiologically Inspired Control of Engineered Flapping Flight", "book_title": "AIAA Infotech@Aerospace Conference 2009", "author": [ { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Stoner", "given_name": "Jeremiah R.", "clpid": "Stone-J-R" }, { "family_name": "Dorothy", "given_name": "Michael R.", "clpid": "Dorothy-M-R" } ], "abstract": "This article presents a new control approach for engineered \nflapping flight with many interacting degrees of freedom. This paper explores the applications of neurobiologically\ninspired control systems in the form of Central Pattern Generators (CPG) to generate wing trajectories for potential flapping flight MAVs. We present a rigorous mathematical and control theoretic framework to design complex three dimensional motions of flapping wings. Most \nflapping flight demonstrators are mechanically limited in generating the wing trajectories. Because CPGs lend themselves to more biological examples of flight, a novel\nrobotic model has been developed to emulate the flight of bats. This model has shoulder and leg joints totaling 10 degrees of freedom for control of wing properties. Results of wind tunnel experiments and numerical simulation of CPG-based flight control validate the effectiveness of the proposed neurobiologically inspired control approach.", "doi": "10.2514/6.2009-1929", "isbn": "978-1-60086-979-2", "publisher": "American Institute of Aeronautics and Astronautics (AIAA)", "place_of_publication": "Reston, VA", "publication_date": "2009-04", "pages": "Art. No. 2009-1929" }, { "id": "authors:0sd75-eeg05", "collection": "authors", "collection_id": "0sd75-eeg05", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161129-121035179", "type": "book_section", "title": "Biologically Inspired Monocular Vision Based Navigation and Mapping in GPS-Denied Environments", "book_title": "AIAA Infotech@Aerospace Conference", "author": [ { "family_name": "\u00c7elik", "given_name": "Koray", "clpid": "\u00c7elik-K" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Clausman", "given_name": "Matthew", "clpid": "Clausman-M" }, { "family_name": "Somani", "given_name": "Arun", "clpid": "Somani-A-K" } ], "abstract": "This paper presents an in-depth theoretical study of bio-vision inspired feature extraction and depth perception method integrated with vision-based simultaneous localization and mapping (SLAM). We incorporate the key functions of developed visual cortex in several advanced species, including humans, for depth perception and pattern recognition. Our navigation strategy assumes GPS-denied manmade environment consisting of orthogonal walls, corridors and doors. By exploiting the architectural features of the indoors, we introduce a method for gathering useful landmarks from a monocular camera for SLAM\nuse, with absolute range information without using active ranging sensors. Experimental results show that the system is only limited by the capabilities of the camera and the\navailability of good corners. The proposed methods are experimentally validated by our self-contained MAV inside a conventional building.", "doi": "10.2514/6.2009-1962", "isbn": "978-1-60086-979-2", "publisher": "AIAA", "place_of_publication": "Reston, VA", "publication_date": "2009-04", "pages": "Art. No.-2009" }, { "id": "authors:y6shf-4hw45", "collection": "authors", "collection_id": "y6shf-4hw45", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161130-072236304", "type": "book_section", "title": "Attitude and Phase Synchronization of Formation Flying Spacecraft: Lagrangian Approach", "book_title": "AIAA Guidance, Navigation and Control Conference and Exhibit : 18 August 2008 - 21 August 2008, Honolulu, Hawaii", "author": [ { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Ahsun", "given_name": "Umair", "clpid": "Ahsun-Umair" }, { "family_name": "Slotine", "given_name": "Jean-Jacques", "orcid": "0000-0002-7161-7812", "clpid": "Slotine-J-J-E" } ], "abstract": "This article presents a unified synchronization framework with application to precision formation flying spacecraft. Central to the proposed innovation, in applying synchroniza-\ntion to both translational and rotational dynamics in the Lagrangian form, is the use of the distributed stability and performance analysis tool, called contraction analysis that yields exact nonlinear stability proofs. The proposed decentralized tracking control law synchronizes the attitude of an arbitrary number of spacecraft into a common time-varying trajectory with global exponential convergence. Moreover, a decentralized translational tracking control law based on phase synchronization is presented, thus enabling coupled translational and rotational maneuvers. While the translational dynamics can be adequately controlled by linear control laws, the proposed method permits highly nonlinear systems with nonlinearly coupled inertia matrices such as the attitude dynamics of space-craft whose large and rapid slew maneuvers justify the nonlinear control approach. The\nproposed method integrates both the trajectory tracking and synchronization problems in a single control framework.", "doi": "10.2514/6.2008-6472", "isbn": "9781600869990", "publisher": "American Institute of Aeronautics and Astronautics (AIAA)", "place_of_publication": "Reston, VA", "publication_date": "2008-08", "pages": "AIAA 2008-6472" }, { "id": "authors:6mktx-z1j79", "collection": "authors", "collection_id": "6mktx-z1j79", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161221-113250801", "type": "book_section", "title": "MVCSLAM: Mono-Vision Corner SLAM for Autonomous Micro-Helicopters in GPS Denied Environments", "book_title": "AIAA Guidance, Navigation and Control Conference and Exhibit 2008", "author": [ { "family_name": "\u00c7elik", "given_name": "Koray", "clpid": "\u00c7elik-K" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Somani", "given_name": "Arun K.", "clpid": "Somani-A-K" } ], "abstract": "We present a real-time vision navigation and ranging method (VINAR) for the purpose of Simultaneous Localization and Mapping (SLAM) using monocular vision. Our navigation strategy assumes a GPS denied unknown environment, whose indoor architecture is represented via corner based feature points obtained through a monocular camera. We experiment on a case study mission of vision based SLAM through a conventional maze of corridors in a large building with an autonomous Micro Aerial Vehicle (MAV). We propose a method for gathering useful landmarks from a monocular camera for SLAM use. We make use of the corners by exploiting the architectural features of the manmade indoors.", "doi": "10.2514/6.2008-6670", "isbn": "978-1-60086-999-0", "publisher": "American Institute of Aeronautics and Astronautics (AIAA)", "place_of_publication": "Reston, VA", "publication_date": "2008-08", "pages": "Art. No. 2008-6670" }, { "id": "authors:vr2e0-bqz13", "collection": "authors", "collection_id": "vr2e0-bqz13", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161221-111102659", "type": "book_section", "title": "Sensor Based Path Planning in Highly Constrained Environments for Agile Autonomous Vehicles", "book_title": "AIAA Guidance, Navigation and Control Conference and Exhibit 2008", "author": [ { "family_name": "Berg-Taylor", "given_name": "Kito", "clpid": "Berg-Taylor-K" }, { "family_name": "Seo", "given_name": "Keehong", "clpid": "Seo-Keehong" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "This paper presents at a class of new methods which explore and describe an unstructured environment according to the free space as seen by a vehicle within the environment.\nThe proposed methods use such sensor-based information to present a safe, goal-seeking path through the environment. The methods are suitable to both online, reactive pathnding and obstacle avoidance as well as online or offline global navigation and goal-seeking behaviours. Experimental results on ground vehicles and in simulation are presented to demonstrate the path-planning capabilities of the proposed methods.", "doi": "10.2514/6.2008-7168", "isbn": "9781605608082", "publisher": "American Institute of Aeronautics and Astronautics (AIAA)", "place_of_publication": "Reston, VA", "publication_date": "2008-08", "pages": "Art. No. 2008-7168" }, { "id": "authors:h0mb6-pfg24", "collection": "authors", "collection_id": "h0mb6-pfg24", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161122-143023693", "type": "book_section", "title": "Mono-vision corner SLAM for indoor navigation", "book_title": "IEEE International Conference on Electro/Information Technology, 2008", "author": [ { "family_name": "\u00c7elik", "given_name": "Koray", "clpid": "\u00c7elik-K" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Somani", "given_name": "Arun", "clpid": "Somani-A-K" } ], "abstract": "We present a real-time monocular vision based range measurement method for Simultaneous Localization and Mapping (SLAM) for an Autonomous Micro Aerial Vehicle (MAV) with significantly constrained payload. Our navigation strategy assumes a GPS denied manmade environment, whose indoor architecture is represented via corner based feature points obtained through a monocular camera. We experiment on a case study mission of vision based path-finding through a conventional maze of corridors in a large building.", "doi": "10.1109/EIT.2008.4554326", "isbn": "978-1-4244-2029-2", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2008-05", "pages": "343-348" }, { "id": "authors:sfcqw-wdq90", "collection": "authors", "collection_id": "sfcqw-wdq90", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161122-135542529", "type": "book_section", "title": "Development of a Car-like Online Navigation Testbed", "book_title": "2008 IEEE International Conference on Electro/Information Technology", "author": [ { "family_name": "Berg-Taylor", "given_name": "Kito", "clpid": "Berg-Taylor-K" }, { "family_name": "Seo", "given_name": "Keehong", "clpid": "Seo-Keehong" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "We present new realtime path planning and collision avoidance algorithms for an autonomous rover equipped with a laser range finder to be used as a platform for multi-agent navigation and control in unknown environments. For successful navigation, such tasks as localization, map-building, and collision avoidance should be handled at the vehicle level. The proposed architecture covers these aspects of robotic path- planning in a modular and robust manner, allowing quicker development of more sophisticated path-planners. Using a conventional SLAM algorithm, a feature map and the location of the vehicle is obtained. The information for orientation and distance of the obstacles ahead is available from a laser range finder. The proposed collision avoidance algorithm provides multiple paths to guide the vehicle through the environment. The system acts as a self-contained extendable platform for development and testing of high-level pathfinders.", "doi": "10.1109/EIT.2008.4554325", "isbn": "978-1-4244-2029-2", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2008-05", "pages": "337-342" }, { "id": "authors:vptdk-feh08", "collection": "authors", "collection_id": "vptdk-feh08", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161122-133156700", "type": "book_section", "title": "Cooperative Robot Control and Synchronization of Lagrangian Systems", "book_title": "46th IEEE Conference on Decision and Control, 2007", "author": [ { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Slotine", "given_name": "Jean-Jacques E.", "clpid": "Slotine-J-J-E" } ], "abstract": "This article presents a simple synchronization framework that can be directly applied to cooperative control of multi-agent systems and oscillation synchronization in robotic manipulation and teleoperation. A dynamical network of multiple Lagrangian systems is constructed by adding diffusive couplings to otherwise freely moving or flying robots. The proposed decentralized tracking control law synchronizes an arbitrary number of robots into a common trajectory with global exponential convergence. The proposed strategy is much simpler than earlier work in terms of both the computational load and the required signals. Furthermore, in contrast with prior work which used simple double integrator models, the proposed method permits highly nonlinear systems and is further extended to time-delayed communications, adaptive control, partial-joint coupling, and leader-follower networks.", "doi": "10.1109/CDC.2007.4434036", "isbn": "978-1-4244-1497-0", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2007-12", "pages": "2504-2509" }, { "id": "authors:5983c-yvz35", "collection": "authors", "collection_id": "5983c-yvz35", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161221-102258243", "type": "book_section", "title": "New Control Strategies for Underactuated Tethered Formation Flight Spacecraft", "book_title": "AIAA Guidance, Navigation and Control Conference and Exhibit 2007", "author": [ { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Slotine", "given_name": "Jean-Jacques", "clpid": "Slotine-J-J-E" }, { "family_name": "Miller", "given_name": "David", "orcid": "0000-0001-6099-0614", "clpid": "Miller-D-W" } ], "abstract": "We introduce a decentralized attitude control strategy that can dramatically reduce the usage of propellant, by taking full advantage of the physical coupling of the tether. Moti-\nvated by a controllability analysis, indicating that both spin-up and relative attitudes are fully controllable by the reaction wheels, we report the first propellant-free underactuated linear and nonlinear control results for tethered formation flying spacecraft. We take a nonlinear control approach to underactuated tethered formation flying spacecraft, whose lack of full state feedback linearizability, along with their complex nonholonomic behavior, characterizes the difficult nonlinear control problem. We introduce several nonlinear control laws that are more efficient in tracking time-varying trajectories than linear control. We also extend our decentralized control approach to underactuated tethered systems,\nthereby eliminating the need for any inter-satellite communication.", "doi": "10.2514/6.2007-6858", "isbn": "9781563479045", "publisher": "American Institute of Aeronautics and Astronautics", "place_of_publication": "Reston, VA", "publication_date": "2007-08-23", "pages": "Art. No. 2007-6858" }, { "id": "authors:q43q3-svn21", "collection": "authors", "collection_id": "q43q3-svn21", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161221-100404214", "type": "book_section", "title": "Application of Synchronization to Cooperative Control and Formation Flight of Spacecraft", "book_title": "AIAA Guidance, Navigation and Control Conference and Exhibit 2007", "author": [ { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Ahsun", "given_name": "Umair", "clpid": "Ahsun-Umair" }, { "family_name": "Slotine", "given_name": "Jean-Jacques", "clpid": "Slotine-J-J-E" }, { "family_name": "Miller", "given_name": "David", "orcid": "0000-0001-6099-0614", "clpid": "Miller-D-W" } ], "abstract": "This article presents a simple synchronization framework with application to synchronization control of formation \nflying spacecraft. A dynamical network of multiple Lagrangian systems is constructed by adding diffusive couplings to otherwise freely flying spacecraft. The proposed tracking control law synchronizes an arbitrary number of spacecraft into a common time-varying trajectory with global exponential convergence. The proposed strategy is much simpler than earlier work in terms of both the computational load and the required signals. Furthermore, in contrast with prior work which used simple double integrator models, the proposed method permits highly nonlinear systems and is further extended to adaptive synchronization, partial-state coupling, and time-delayed communications.", "doi": "10.2514/6.2007-6861", "isbn": "9781563479045", "publisher": "American Institute of Aeronautics and Astronautics (AIAA)", "place_of_publication": "Reston, VA", "publication_date": "2007-08", "pages": "Art. No. 2007-6861" }, { "id": "authors:tdmae-5j834", "collection": "authors", "collection_id": "tdmae-5j834", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161130-065345609", "type": "book_section", "title": "Nonlinear Model Reduction and Decentralized Control of Tethered Formation Flight by Oscillation Synchronization", "book_title": "AIAA Guidance, Navigation, and Control Conference and Exhibit 2006", "author": [ { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" } ], "abstract": "This paper describes a fully decentralized nonlinear control law for spinning tethered formation flight, based on exploiting geometric symmetries to reduce the original nonlinear dynamics into simpler stable dynamics. Motivated by oscillation synchronization in biological systems, we use contraction theory to prove that a control law stabilizing a single-tethered spacecraft can also stabilize arbitrary large circular arrays of spacecraft, as well as the three inline configuration. The convergence result is global and exponential. Numerical simulations and experimental results using the SPHERES testbed validate the\nexponential stability of the tethered formation arrays by implementing a tracking control law derived from the reduced dynamics.", "doi": "10.2514/6.2006-6589", "isbn": "978-1-62410-046-8", "publisher": "American Institute of Aeronautics and Astronautics (AIAA)", "place_of_publication": "Reston, VA", "publication_date": "2006-08", "pages": "Art. No.2006-6589" }, { "id": "authors:r3bx2-2rd03", "collection": "authors", "collection_id": "r3bx2-2rd03", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161122-120253690", "type": "book_section", "title": "SPHERES Tethered Formation Flight Testbed: Advancements in Enabling NASA's SPECS Mission", "book_title": "Advances in Stellar Interferometry", "author": [ { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Adams", "given_name": "Danielle", "clpid": "Adams-Danielle" }, { "family_name": "Saenz-Otero", "given_name": "Alvar", "clpid": "Saenz-Otero-A" }, { "family_name": "Kong", "given_name": "Edmund M.", "clpid": "Kong-Edmund-M" }, { "family_name": "Miller", "given_name": "David W.", "orcid": "0000-0001-6099-0614", "clpid": "Miller-D-W" }, { "family_name": "Leisawitz", "given_name": "David", "clpid": "Leisawitz-D-T" }, { "family_name": "Lorenzini", "given_name": "Enrico", "clpid": "Lorenzini-E" }, { "family_name": "Sell", "given_name": "Steve", "clpid": "Sell-S" } ], "contributor": [ { "family_name": "Monnier", "given_name": "John D.", "clpid": "Monnier-J-D" }, { "family_name": "Sch\u00f6ller", "given_name": "Markus", "clpid": "Sch\u00f6ller-M" }, { "family_name": "Danchi", "given_name": "William C.", "clpid": "Danchi-W-C" } ], "abstract": "This paper reports on efforts to control a tethered formation flight spacecraft array for NASA's SPECS mission using the SPHERES test-bed developed by the MIT Space Systems Laboratory. Specifically, advances in methodology and experimental results realized since the 2005 SPIE paper are emphasized. These include a new test-bed setup with a reaction wheel assembly, a novel relative attitude measurement system using force torque sensors, and modeling of non-ideal tethers to account for tether vibration modes. The nonlinear equations of motion of multi-vehicle tethered spacecraft with elastic flexible tethers are derived from Lagrange's equations. The controllability analysis indicates that both array resizing and spin-up are fully controllable by the reaction wheels and the tether motor, thereby saving thruster fuel consumption. Based upon this analysis, linear and nonlinear controllers have been successfully implemented on the tethered SPHERES testbed, and tested at the NASA MSFC's flat floor facility using two and three SPHERES configurations.", "doi": "10.1117/12.670489", "isbn": "0-8194-6333-7", "publisher": "Society of Photo-Optical Instrumentation Engineers (SPIE)", "place_of_publication": "Bellingham, WA", "publication_date": "2006-06-27", "pages": "Art. No. 62680B" }, { "id": "authors:96td5-myt03", "collection": "authors", "collection_id": "96td5-myt03", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161122-111732319", "type": "book_section", "title": "SPHERES Tethered Formation Flight Testbed: Application to NASA's SPECS Mission", "book_title": "UV/Optical/IR Space Telescopes: Innovative Technologies and Concepts II", "author": [ { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Kong", "given_name": "Edmund M.", "clpid": "Kong-Edmund-M" }, { "family_name": "Miller", "given_name": "David W.", "orcid": "0000-0001-6099-0614", "clpid": "Miller-D-W" } ], "contributor": [ { "family_name": "MacEwen", "given_name": "Howard A.", "clpid": "MacEwen-H-A" } ], "abstract": "This paper elaborates on theory and experiment of the formation flight control for the future space-borne tethered interferometers. The nonlinear equations of multi-vehicle tethered spacecraft system are derived by Lagrange equations and decoupling method. The preliminary analysis predicts unstable dynamics depending on the direction of the tether motor. The controllability analysis indicates that both array resizing and spin-up are fully controllable only by the reaction wheels and the tether motor, thereby eliminating the need for thrusters. Linear and nonlinear decentralized control techniques have been implemented into the tethered SPHERES testbed, and tested at the NASA MSFC's flat floor facility using two and three SPHERES configurations. The nonlinear control using feedback linearization technique performed successfully in both two SPHERES in-line configuration and three triangular configuration while varying the tether length. The relative metrology system, using the ultra sound metrology system and the inertial sensors as well as the decentralized nonlinear estimator, is developed to provide necessary state information.", "doi": "10.1117/12.614643", "isbn": "9780819459046", "publisher": "Society of Photo-Optical Instrumentation Engineers (SPIE)", "place_of_publication": "Bellingham, WA", "publication_date": "2005-08-24", "pages": "Art. No. 58990L" }, { "id": "authors:cxrpz-68x31", "collection": "authors", "collection_id": "cxrpz-68x31", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161121-130021663", "type": "book_section", "title": "Integrated modeling of optical performance for the Terrestrial Planet Finder structurally connected interferometer", "book_title": "Modeling and Systems Engineering for Astronomy", "author": [ { "family_name": "LoBosco", "given_name": "David M.", "clpid": "LoBosco-D-M" }, { "family_name": "Blaurock", "given_name": "Carl", "clpid": "Blaurock-C" }, { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Miller", "given_name": "David W.", "orcid": "0000-0001-6099-0614", "clpid": "Miller-D-W" } ], "contributor": [ { "family_name": "Craig", "given_name": "Simon C.", "clpid": "Craig-S-C" }, { "family_name": "Cullum", "given_name": "Martin J.", "clpid": "Cullum-M-J" } ], "abstract": "The Terrestrial Planet Finder (TPF) mission, to be launched in 2014 as a part of NASA's Origins Program, will search for Earth-like planets orbiting other stars. One main concept under study is a structurally connected interferometer. Integrated modeling of all aspects of the flight system is necessary to ensure that the stringent dynamic stability requirements imposed by the mission are met. The MIT Space Systems Laboratory has developed a suite of analysis tools known as DOCS (Disturbances Optics Controls Structures) that provides a MATLAB environment for managing integrated models and performing analysis and design optimization. DOCS provides a framework for identifying critical subsystem design parameters and efficiently computing system performance as a function of subsystem design. Additionally, the gradients of the performance outputs with respect to design variables can be analytically computed and used for automated exploration and optimization of the design space. The TPF integrated model consists of a structural finite element model, optical performance model, reaction wheel isolation stage, and attitude/optical control systems. The integrated model is expandable and upgradeable due to the modularity of the state-space subsystem models. Optical performance under reaction wheel disturbances is computed, and the effects of changing design parameters are explored. The results identify redesign options that meet performance requirements with improved margins, reduced cost and minimized risk.", "doi": "10.1117/12.550929", "isbn": "0-8194-5429-X", "publisher": "Society of Photo-Optical Instrumentation Engineers (SPIE)", "place_of_publication": "Bellingham, WA", "publication_date": "2004-09-16", "pages": "278-289" }, { "id": "authors:x7weq-emn82", "collection": "authors", "collection_id": "x7weq-emn82", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161130-104041149", "type": "book_section", "title": "Multidisciplinary Control of a Sparse Interferometric Array Satellite Testbed", "author": [ { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "LoBosco", "given_name": "David M.", "clpid": "LoBosco-D-M" }, { "family_name": "Miller", "given_name": "David W.", "orcid": "0000-0001-6099-0614", "clpid": "Miller-D-W" }, { "family_name": "Blaurock", "given_name": "Carl", "clpid": "Blaurock-C" } ], "abstract": "The MIT Adaptive Reconnaissance Golay-3 Optical Satellite (ARGOS) is a wide-angle Fizeau interferometer spacecraft testbed. Designing a space-based interferometer, which requires such high tolerances on pointing and alignment for its apertures, presents unique multidisciplinary challenges in the areas of structural dynamics, controls and multi-aperture phasing active optics. In meeting these challenges, emphasis is placed on modularity in spacecraft subsystems and optics as a means of allowing expandability and upgradeability. For the interferometer to function properly, unique methods of coherent wave front sensing are developed and used for error detection in control of the Fast Steering Mirrors (FSMs). The space environment is simulated by floating ARGOS on a frictionless air-bearing that allows it to track fast moving satellites such as the International Space Station (ISS), planets or point stars. A System Identification is performed on ARGOS to determine its dynamic properties and to design optimal controllers for\nthe Attitude Control System (ACS). ACS sensors include an electronic compass with a 2-axis tip-tilt sensor, a viewfinder camera with centroiding algorithm, and a 3-axis rate gyroscope. Nonlinear, quaternion-based control is employed using reaction wheels as the spacecraft's actuators.", "doi": "10.2514/6.2003-5433", "publisher": "American Institute of Aeronautics and Astronautics (AIAA)", "publication_date": "2003-08" }, { "id": "authors:vpc73-16z28", "collection": "authors", "collection_id": "vpc73-16z28", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161121-093035571", "type": "book_section", "title": "Design and implementation of sparse aperture imaging systems", "book_title": "Highly Innovative Space Telescope Concepts", "author": [ { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Miller", "given_name": "David W.", "orcid": "0000-0001-6099-0614", "clpid": "Miller-D-W" }, { "family_name": "de-Weck", "given_name": "Olivier L.", "clpid": "de-Weck-O-L" } ], "contributor": [ { "family_name": "MacEwen", "given_name": "Howard A.", "clpid": "MacEwen-H-A" } ], "abstract": "In order to better understand the technological difficulties involved in designing and building a sparse aperture array, the challenge of building a white light Golay-3 telescope was undertaken. The MIT Adaptive Reconnaissance Golay-3 Optical Satellite (ARGOS) project exploits wide-angle Fizeau interferometer technology with an emphasis on modularity in the optics and spacecraft subsystems. Unique design procedures encompassing the nature of coherent wavefront sensing, control and combining as well as various system engineering aspects to achieve cost effectiveness, are developed. To demonstrate a complete spacecraft in a 1-g environment, the ARGOS system is mounted on a frictionless air-bearing, and has the ability to track fast orbiting satellites like the ISS or the planets. Wavefront sensing techniques are explored to mitigate initial misalignment and to feed back real-time aberrations into the optical control loop. This paper presents the results and the lessons learned from the conceive, design and implementation phases of ARGOS. A preliminary assess-ment shows that the beam combining problem is the most challenging aspect of sparse optical arrays. The need for optical control is paramount due to tight beam combining tolerances. The wavefront sensing/control requirements appear to be a major technology and cost driver.", "doi": "10.1117/12.460077", "isbn": "0-8194-4628-9", "publisher": "Society of Photo-Optical Instrumentation Engineers (SPIE)", "place_of_publication": "Bellingham, WA", "publication_date": "2002-12-01", "pages": "181-192" }, { "id": "authors:sjrvh-hxe54", "collection": "authors", "collection_id": "sjrvh-hxe54", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161220-112255420", "type": "book_section", "title": "Design, Implementation and Operation of a Sparse Aperture Imaging Satellite Testbed", "author": [ { "family_name": "Chung", "given_name": "Soon-Jo", "orcid": "0000-0002-6657-3907", "clpid": "Chung-Soon-Jo" }, { "family_name": "Miller", "given_name": "David W.", "orcid": "0000-0001-6099-0614", "clpid": "Miller-D-W" } ], "abstract": "In order to better understand the technological difficulties involved in designing and building a sparse aperture array, the challenge of building a white light Golay-3 telescope was undertaken. The MIT Adaptive Reconnaissance Golay-3 Optical Satellite (ARGOS) project exploits wide-angle Fizeau interferometer technology with an emphasis on modularity in the optics and spacecraft subsystems. Unique design procedures encompassing the nature of coherent wavefront sensing, control and combining as well as various system engineering aspects to achieve cost effectiveness, are developed. To demonstrate a complete spacecraft in a 1-g environment, the ARGOS system is mounted on a frictionless air-bearing, and has the ability to track fast orbiting satellites like the ISS or the planets. Wavefront sensing techniques are explored to mitigate initial misalignment and to feed back real-time aberrations into the optical control loop. This paper presents the results and the lessons learned from the conceive, design, implement and operate phases of ARGOS. A preliminary assessment shows that the beam combining problem is the most challenging aspect of sparse optical arrays. The need for optical control is paramount due to tight beam combining tolerances. The wavefront sensing/control requirements appear to be a major technology and cost driver.", "publisher": "American Institute of Aeronautics and Astronautics", "publication_date": "2002-08" } ]