Browsing by Author "Chu, Tzu-Chiang"

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Robust control of the robot manipulator via an improved sliding mode scheme
(2007)
Liang, Yew-Wen
;
Xu, Sheng-Dong
;
Chu, Tzu-Chiang
;
電控工程研究所
;
Institute of Electrical and Control Engineering
In this paper, an improved Sliding Mode Control (SMC) scheme, reformed from the conventional SMC approaches, is developed for position tracking of a robot manipulator with parameter uncertainties and external disturbances. The improved SMC scheme, which uses saturation-type SMC laws, is shown to be able to surpass the level of uniformly ultimate boundedness to achieve asymptotic stability. In addition, the presented first-order SMC laws are continuous; as a result, this scheme can also alleviate the undesirable chattering behavior that is characteristic of sign-type SMC laws. Simulation results demonstrate the benefits of the proposed scheme.
VSC reliable design with application to spacecraft attitude tracking
(2005)
Liang, Yew-Wen
;
Xu, Sheng-Dong
;
Chu, Tzu-Chiang
;
Tsai, Che-Lun
;
Cheng, Chiz-Chung
This study investigates variable structure reliable control issues of nonlinear systems and its applications to spacecraft attitude tracking problems. Both passive and active reliable control laws are proposed using Variable Structure Control (VSC) technique. The passive one must know which group of actuators is allowed to fail, while the active one must accompany a fault detection and diagnosis (FDD) scheme. Both the reliable controllers need not the solution of Hamilton-Jacobi equation or inequality, which are essentials in optimal approaches such as reliable LQR and H-infinity designs. As a matte of fact, the VSC approach is able to relax the computational latency in control law computing. The proposed reliable designs are also applied to spacecraft attitude tracking problems to explain their effectiveness and benefits. Finally, simulation results and comparisons between LQR and VSC reliable designs are given to illustrate the merits of the proposed scheme.