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Distributed Cooperative Attitude Tracking for Multiple Flexible Spacecraft under a Directed Graph

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Distributed Cooperative Attitude Tracking for Multiple Flexi...

第三十八届中国控制会议

作者： Lei Wang Zhuoyue Song Housheng Su Yiqun Zou Xiafei Tang State Key Laboratory of Intelligent Control and Decision of Complex Systems and School of Automation Beijing Institute of Technology School of Automation Huazhong University of Science and Technology School of Automation Central South University School of Electrical and Information Engineering Changsha University of Science and Technology

This paper is concerned with the problem of cooperative attitude tracking and vibration reduction for multiple flexible spacecraft without modal variable measurement under a directed communication topology. Firstly, a distributed attitude synchronization control law for MRPs representation is proposed in the absence of external disturbances, where the modal information is obtained using a modal variable estimator. To deal with a more practical case that the spacecraft are affected by external disturbances, the control law is further modified by integrating a disturbance observer and a feedforward compensating scheme,in which the lumped disturbances including the external disturbances and errors of the estimated modal information are observed and compensated in finite time. Under this enhanced control scheme, the attitude tracking errors and vibration variables will converge to zero even in the presence of external disturbances, and the controller is continuous and chattering-free. Besides,compared with the existing results, the communication graph in this paper is assumed to be directed and contain a spanning tree with the virtual leader as the root node. A numerical example is illustrated to demonstrate the effectiveness of the proposed results.

关键词： Attitude tracking Multiple flexible spacecraft Directed graph External disturbance

Consensus control of linear multi-agent systems with distributed adaptive protocols

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Consensus control of linear multi-agent systems with distrib...

American control Conference (ACC)

作者： Zhongkui Li Xiangdong Liu Wei Ren Lihua Xie Key laboratory for Intelligent Control & Decision of Complex Systems Beijing Institute of Technology Beijing P. R. China Department of Electrical Engineering University of California Riverside CA USA School of Electrical and Electronic Engineering Nanyang Technological University Singapore

ISBN: (纸本)9781457710957

This paper considers the distributed consensus problem of multi-agent systems with general continuous-time linear time-invariant dynamics. Based on the relative output information of neighboring agents, two distributed adaptive dynamic consensus protocols are proposed, namely, the edge-based adaptive protocol which assigns a time-varying coupling weight to each edge in the communication graph and the node-based adaptive protocol which uses a time-varying coupling weight for each node. These two adaptive protocols are designed to ensure that consensus is reached in a fully distributed fashion for any undirected connected communication graphs without using any global information. A sufficient condition for the existence of these adaptive protocols is that each agent is stabilizable and detectable. The case with switching communication graphs is also studied.

关键词： Protocols Eigenvalues and eigenfunctions Couplings Switches Linear matrix inequalities Laplace equations Lyapunov methods

Marker or Markerless? Mode-Switchable Optical Tactile Sensing for Diverse Robot Tasks

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arXiv 2024年

作者： Ou, Ni Chen, Zhuo Luo, Shan The State Key Laboratory of Intelligent Control and Decision of Complex Systems Beijing Institute of Technology Beijing100081 China The Robot Perception Lab. Centre for Robotics Research Department of Engineering King’s College London LondonWC2R 2LS United Kingdom

Optical tactile sensors play a pivotal role in robot perception and manipulation tasks. The membrane of these sensors can be painted with markers or remain markerless, enabling them to function in either marker or markerless mode. However, this uni-modal selection means the sensor is only suitable for either manipulation or perception tasks. While markers are vital for manipulation, they can also obstruct the camera, thereby impeding perception. The dilemma of selecting between marker and markerless modes presents a significant obstacle. To address this issue, we propose a novel mode-switchable optical tactile sensing approach that facilitates transitions between the two modes. The marker-to-markerless transition is achieved through a generative model, whereas its inverse transition is realized using a sparsely supervised regressive model. Our approach allows a single-mode optical sensor to operate effectively in both marker and markerless modes without the need for additional hardware, making it well-suited for both perception and manipulation tasks. Extensive experiments validate the effectiveness of our method. For perception tasks, our approach decreases the number of categories that include misclassified samples by 2 and improves contact area segmentation IoU by 3.53%. For manipulation tasks, our method attains a high success rate of 92.59% in slip detection. Code, dataset and demo videos are available at the project website https://***/Marker-Markerless-Transition/ Copyright © 2024, The Authors. All rights reserved.

关键词： Tactile sensors

Distributed computation of linear matrix equations: An optimization perspective

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arXiv 2017年

作者： Zeng, Xianlin Liang, Shu Hong, Yiguang Chen, Jie Key Laboratory of Intelligent Control and Decision of Complex Systems School of Automation Beijing Institute of Technology Beijing100081 China Key Laboratory of Knowledge Automation for Industrial Processes of Ministry of Education School of Automation and Electrical Engineering University of Science and Technology Beijing Beijing100083 China Key Laboratory of Systems and Control Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing100190 China Ministry of Education Beijing100081 China

This paper investigates the distributed computation of the well-known linear matrix equation in the form of AXB = F, with the matrices A, B, X, and F of appropriate dimensions, over multiagent networks from an optimization perspective. In this paper, we consider the standard distributed matrix-information structures, where each agent of the considered multi-agent network has access to one of the sub-block matrices of A, B, and F. To be specific, we first propose different decomposition methods to reformulate the matrix equations in standard structures as distributed constrained optimization problems by introducing substitutional variables;we show that the solutions of the reformulated distributed optimization problems are equivalent to least squares solutions to original matrix equations;and we design distributed continuous-time algorithms for the constrained optimization problems, even by using augmented matrices and a derivative feedback technique. Moreover, we prove the exponential convergence of the algorithms to a least squares solution to the matrix equation for any initial condition. Copyright © 2017, The Authors. All rights reserved.

关键词： Continuous time systems

Design and dynamic analysis for Amoeba-like robot's turning-mechanism applied with spring and damp system

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Design and dynamic analysis for Amoeba-like robot's turning-...

International Conference on Advanced Robotics and Mechatronics (ICARM)

作者： Xiang Dong HengHui Sun Zeng Fu Wang Long Cheng Institute of Intelligent Machines Chinese Academy of Sciences Hefei Anhui CN The State Key Lab. of Management and Control for Complex Systems Institute of Automation Chinese Academy of Sciences Beijing Beijing CN

ISBN: (纸本)9781509033652

A new turning-mechanism for Amoeba-like Robot was proposed in this paper, which based on the amoeba-like robot kinematics characteristics of tail contracting and skin flipping. First, one kind of variable-speed node composed of the spring and damp was designed. Because of the existing of the variable-speed nodes, the velocities of the two strip-skins depended not only on the velocities of threads that gone through the variable-speed nodes, but also on the spring and damp it contained. So, although the velocities of threads that induced the velocities of the strip-skins were the same, the velocities of the strip-skins still can be different since the variable-speed nodes existed. That difference in velocities made the turning movement possible. Second, the dynamic model for the turning movement of the Amoeba-like Robot was established and analyzed. The analysis results included the angular velocity and angle curve related to time, which were computed with the dynamic model when shortening speed of thread's length was constant. The results achieved in this paper provided an important basic for the research on the behaviors and control strategy of amoeba-like robot. The new turning-mechanism can be popularized to the tracked mobile robot, for it provided a new and available turning method.

关键词： Conferences Robots Mechatronics

Design and optimization of a high-bandwidth low-speed high-torque permanent magnetic synchronous motor

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Diangong Jishu Xuebao/Transactions of China Electrotechnical Society 2014年 29卷 108-114页

作者： Chen, Hao Liu, Xiangdong Zhao, Jing Key Laboratory for Intelligent Control and Decision of Complex Systems Beijing Institute of Technology Beijing100081 China Beijing Institute of Technology Beijing100081 China

In order to get a better dynamic response for actuator in condition of low-speed, a permanent magnet synchronous motor (PMSM) in direct-drive application with the characteristics of high-bandwidth, low-speed and high-torque was designed in this paper. Based on the requirement of high-bandwidth, the motor's inertia should be kept low to acquire a large acceleration. The limitation of space size makes motor work in non-linear region, which will increase the electrical capacity. This paper took the relationship between inertia, physical size and electrical capacity into consideration and an optimal result was selected by the method of cyclic iteration. According to the characteristics of large-torque motors, the reason of low power factor was further analyzed. In order to improve the motor performance, optimal design was taken on modified Taguchi method based on time-stepping Finite Element Method (FEM) in this paper. First, five structural parameters (pole-arc coefficient, etc.) were taken as optimization variables and four motor performance indexes (power factor, etc.) as optimization objectives. Then, the multi-objective multivariable optimization was adopted. Finally, The results of FEM and prototype experiment verified the advantage and effectiveness of the modified Taguchi method. ©, 2014, Diangong Jishu Xuebao/Transactions of China Electrotechnical Society. All right reserved.

关键词： Finite element method

Distributed Momentum-based Frank-Wolfe Algorithm for Stochastic Optimization

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arXiv 2022年

作者： Hou, Jie Zeng, Xianlin Wang, Gang Sun, Jian Chen, Jie The Key Laboratory of Intelligent Control and Decision of Complex Systems School of Automation Beijing Institute of Technology Beijing100081 China Beijing Institute of Technology Chongqing Innovation Center Chongqing401120 China The School of Electronic and Information Engineering Tongji University Shanghai200082 China

—This paper considers distributed stochastic optimization, in which a number of agents cooperate to optimize a global objective function through local computations and information exchanges with neighbors over a network. Stochastic optimization problems are usually tackled by variants of projected stochastic gradient descent. However, projecting a point onto a feasible set is often expensive. The Frank-Wolfe (FW) method has well-documented merits in handling convex constraints, but existing stochastic FW algorithms are basically developed for centralized settings. In this context, the present work puts forth a distributed stochastic Frank-Wolfe solver, by judiciously combining Nesterov’s momentum and gradient tracking techniques for stochastic convex and nonconvex optimization over networks. It is shown that the convergence rate 1 of the proposed algorithm is O(k− 2) for convex optimization, and O(1/log2(k)) for nonconvex optimization. The efficacy of the algorithm is demonstrated by numerical simulations against a number of competing alternatives. Copyright © 2022, The Authors. All rights reserved.

关键词： Momentum

Event-triggered Observability: A Set-membership Perspective

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arXiv 2022年

作者： Zheng, Kaikai Shi, Dawei Chen, Tongwen State Key Laboratory of Intelligent Control and Decision of Complex Systems School of Automation Beijing Institute of Technology Beijing100081 China Department of Electrical and Computer Engineering University of Alberta EdmontonABT6G 1H9 Canada

This work attempts to discuss the observability of linear time-invariant systems with event-triggered measurements. A new notion of observability, namely, ǫ-observability is defined with parameter ǫ, which relates to the worst-case performance of inferring the initial state based on not only the received measurement but also the implicit information in the event-triggering conditions at no-event instants. A criterion is developed to test the proposed ǫ-observability of discrete-time linear systems, based on which an iterative event-triggered set-membership observer is designed to evaluate a set containing all possible values of the state. The proposed set-membership observer is designed as the outer approximation of the ellipsoids predicted based on previous state estimates and the ellipsoids inferred by fusing the received measurement and communication conditions, which is optimal in the sense of trace at each step and is proved to be asymptotically bounded. The efficiency of the proposed event-triggered set-membership state observer is verified by numerical experiments. © 2022, CC BY.

关键词： State estimation

Adaptive control with Nearest-neighbor Previous Instant Compensation for Discrete-time Nonlinear Strict-feedback systems

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Adaptive Control with Nearest-neighbor Previous Instant Comp...

American control Conference

作者： Chenguang Yang Hongbin Ma Bin Xu Mengyin Fu School of Computing and Mathematics the University of Plymouth UK PL4 8AA Key Laboratory of Intelligent Control and Decision of Complex Systems Beijing Institute of Technology Beijing China 100081 School of Automation Northwestern Polytechnical University Xi'an China 710072

ISBN: (纸本)9781457710957

Many nonlinear systems can be modeled by or converted to strict-feedback forms, whose stabilization problem without modeling uncertainties has been extensively discussed in the literature. However, in practice, inevitable modeling uncertainties, especially co-existence of parametric uncertainties and nonparametric uncertainties, will make it very difficult and challenging to achieve desirable control performance. In this background, we consider a challenging adaptive control problem, aiming at asymptotic tracking to any bounded reference signal, in the presence of periodic uncertainties of both parametric and nonparametric types, i.e., periodic time-varying parameters and periodic unknown time-delays in the uncertain nonlinearities, for a class of strict-feedback discrete-time nonlinear systems due to the lack of related research and the increasing demand of digital control in current epoch. To deal with the co-existing various uncertainties, which bring highly-nonlinear coupled effects to the closed-loop system, a novel nearest-neighbor previous instant compensation technique, combined with the lifting approach and the future states prediction, is introduced in this paper to asymptotically fully compensate the effects of uncertainties. With such elaborately constructed adaptive estimation mechanism, the developed discrete-time backstepping adaptive controller can guarantee the closed-loop stability as well as asymptotic output tracking, which have been rigorously established and testified by extensive simulations.

关键词： adaptive control Uncertainty asymptotic tracking discrete-time Nearest neighbor Reference signals Parametric instant control performance Numerical controls compensated