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Wang Y.,Beijing Institute of Control Engineering
Kongzhi Lilun Yu Yingyong/Control Theory and Applications | Year: 2012

In the characteristic modeling theory, the closed-loop system composed of all-coefficient adaptive controller is a complex hybrid system that can not be analyzed in the framework of traditional adaptive control theory, leaving the stability analysis a long-time difficult problem to be solved. This paper investigates a class of minimum phase, single input single output (SISO) nth-order nonlinear system with second relative degree, and proposes a systematic stability analysis framework which transforms the higher order hybrid system to an indirect adaptive control problem with unmodeled dynamics and bounded, slowly varying parameters. Furthermore, this framework can be extended to more complex systems such as the SISO, multi-input multi-output (MIMO), and infinite-dimensional minimum phase systems with higher relative degree.

Wang H.,Beijing Institute of Control Engineering
Robotics and Autonomous Systems | Year: 2011

This paper is devoted to the investigation of adaptive inverse dynamics for free-floating space manipulators (FFSMs) suffering from parameter uncertainties/variations. To overcome the nonlinear parametric problem of the dynamics of FFSMs, we introduce a new regressor matrix called the generalized dynamic regressor. Based on this regressor, and with Lyapunov stability analysis tools, we obtain a new parameter adaptation law and show that the closed-loop system is stable, and that the joint tracking errors converge asymptotically to zero. Simulation results are provided to illustrate the performance of the proposed adaptive algorithm. Furthermore, we conduct a comparative study between adaptive inverse dynamics, prediction error based adaptation, and passivity based adaptation. © 2011 Elsevier B.V. All rights reserved.

Wang H.,Beijing Institute of Control Engineering
Automatica | Year: 2015

In this paper, we investigate the visual tracking problem for robotic systems without image-space velocity measurement, simultaneously taking into account the uncertainties of the camera model and the manipulator kinematics and dynamics. We propose a new image-space observer that exploits the image-space velocity information contained in the unknown kinematics, upon which, we design an adaptive controller without using the image-space velocity signal where the adaptations of the depth-rate-independent kinematic parameter and depth parameter are driven by both the image-space tracking errors and observation errors. The major superiority of the proposed observer-based adaptive controller lies in its simplicity and the separation of the handling of multiple uncertainties in visually servoed robotic systems, thus avoiding the overparametrization problem of the existing work. Using Lyapunov analysis, we demonstrate that the image-space tracking errors converge to zero asymptotically. The performance of the proposed adaptive control scheme is illustrated by a numerical simulation. © 2015 Elsevier Ltd.

Wang H.,Beijing Institute of Control Engineering
Automatica | Year: 2013

This paper investigates the flocking problem of networked nonlinear Euler-Lagrange systems with parametric uncertainties, and they are assumed to interact on directed graphs with a directed spanning tree. We propose an adaptive controller to achieve the flocking objective, and the resultant closed-loop networked system bears the cascade structure. Using a new similarity decomposition approach, a critical-characteristic-root based approach, and the input-output stability analysis, we demonstrate the convergence of the position/velocity synchronization errors among the uncertain nonlinear Euler-Lagrange agents. We also show that the velocities of the Euler-Lagrange systems converge to the weighted average velocity value. Simulation results are provided to demonstrate the performance of the proposed controller. © 2013 Elsevier Ltd. All rights reserved.

Wu H.-X.,Beijing Institute of Control Engineering
Kongzhi Lilun Yu Yingyong/Control Theory and Applications | Year: 2014

The research status of the control theory is analyzed firstly. Then it is presented to construct three new research subjects, i.e., new modeling theory construction, man's intelligence-introduced control method, and computer-based system design, analysis and stability proof with the control theory and method in the engineering. ©, 2014, South China University of Technology. All right reserved.

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