Browsing by Author "Xu, Sheng-Dong"

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A higher-order stabilizability condition for a class of switched systems
(2006)
Liang, Yew-Wen
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Xu, Sheng-Dong
;
Chiang, Chia-Chen
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This study investigates the existence of stabilizing switching rules among a class of unstable nonlinear systems. A high-order checking condition and an associated stabilizing switching rule are presented to implement the stabilizability of the switched systems. An illustrative example is also given to demonstrate the usage and the benefits of the proposed scheme.
A Study of T-S Model-Based SMC Scheme With Application to Robot Control
(2008-11-01)
Liang, Yew-Wen
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Xu, Sheng-Dong
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Liaw, Der-Cherng
;
Chen, Cheng-Chang
;
電控工程研究所
In light of the remarkable benefits and numerous applications of the Takagi-Sugeno (T-S) fuzzy system modeling method and the sliding mode control (SMC) technique, this paper aims to study the design of robust controllers for a set of second-order systems using a combination of these two approaches. The combined scheme is shown to have the merits of both approaches. It alleviates not only the online computational burden by using the T-S fuzzy system model to approximate the original nonlinear one (since most of the system parameters of the T-S model can be computed offline) but also preserves the advantages of rapid response and robustness characteristic of the classic SMC schemes. Moreover, the combined scheme does not need to online compute any nonlinear term of the original dynamics, and the increase in the number of fuzzy rules does not create extra online computational burdens for the scheme. The proposed analytical results are also applied to the control of a two-link robot manipulator and compared with the results using classic SMC design. Simulation results demonstrate the benefits of the proposed scheme.
Construction of stabilizing switching laws among unstable linear systems
(2006)
Liang, Yew-Wen
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Xu, Sheng-Dong
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Chang, Jia-Liang
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Chiang, Chia-Chen
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電控工程研究所
Issues concerning the construction of quadratically stabilizing switching laws among N unstable linear systems are studied in this paper. The obtained results are also employed to study the existence of control laws and quadratically stabilizing switching laws among a class of unstabilizable linear control systems. Finally, the illustrative examples and simulation results show the feasibility and effectiveness of the proposed methods.
Decentralized stabilization of H-infinity fuzzy control for nonlinear multiple time-delay interconnected systems
(2007-03-01)
Hsiao, Feng-Hsiag
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Xu, Sheng-Dong
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Lin, Chia-Yen
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Chou, Yu-Jun
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Chen, Yu-Ching
A robustness design of H infinity fuzzy control is proposed in this paper to overcome the effect of modeling errors between nonlinear multiple time-delay systems and fuzzy models. In terms of Lyapunov's direct method, a stability criterion is derived to guarantee the UUB (uniformly ultimately bounded) stability of nonlinear multiple time-delay interconnected systems with disturbances. Based on this criterion and the decentralized control scheme, a set of fuzzy controllers is then synthesized via the technique of parallel distributed compensation (PDC) to stabilize the nonlinear multiple time-delay interconnected systems and the H infinity control performance is achieved in the mean time.
Decentralized stabilization of neural network linearly interconnected systems via T-S fuzzy control
(2007-05-01)
Hsiao, Feng-Hsiag
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Liang, Yew-Wen
;
Xu, Sheng-Dong
;
Lee, Gwo-Chuan
;
電控工程研究所
The stabilization problem is considered in this study for a neural-network (NN) linearly interconnected system that consists of a number of NN models. First, a linear difference inclusion (LDI) state-space representation is established for the dynamics of each NN model. Then, based on the LDI state-space representation, a stability criterion in terms of Lyapunovs direct method is derived to guarantee the asymptotic stability of closed-loop NN linearly interconnected systems. Subsequently, according to this criterion and the decentralized control.scheme, a set of Takagi-Sugeno (T-S) fuzzy controllers is synthesized to stabilize the NN linearly interconnected system.. Finally, a numerical example with simulations is given to demonstrate the concepts discussed throughout this paper.
Decentralized stabilization of Nonlinear multiple time-delay interconnected systems via h-infinity fuzzy control
(2006)
Hsiao, Feng-Hsiag
;
Xu, Sheng-Dong
;
Lin, Chia-Yen
;
Chou, Yu-Jun
;
Chen, Yu-Ching
A robustness design of H-infinity fuzzy control is proposed in this paper to overcome the effect of modeling error between nonlinear multiple time-delay systems and fuzzy models. In terms of Lyapunov\'s direct method, a stability criterion is hence derived to guarantee the UUB (uniformly ultimately bounded) stability of nonlinear multiple time-delay interconnected systems with disturbances. Based on this criterion and the decentralized control scheme, a set of fuzzy controllers is then synthesized via the technique of parallel distributed compensation (PDC) to stabilize the nonlinear multiple time-delay interconnected systems and the H-infinity control performance is achieved in the mean time.
Design of Midcourse Guidance Laws via a Combination of Fuzzy and SMC Approaches
(2010-04-01)
Chen, Chun-Hone
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Liang, Yew-Wen
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Liaw, Der-Cherng
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Chang, Shih-Tse
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Xu, Sheng-Dong
Issues regarding the design of midcourse guidance laws for antimissiles are addressed. The antimissile is expected to be guided to a place with a desired direction, where a ballistic missile is predicted to pass in the reverse direction, so that the target can be easily found and locked for terminal interception. The predicted location and direction of a ballistic missile may vary with time, due to information update using a trajectory prediction algorithm. To fulfill the guidance performance, the guidance laws are designed by combining the Takagi-Sugeno (T-S) fuzzy approach and the Sliding Mode Control (SMC) technique. Under the designed guidance law, it is shown that the antimissile is able to be efficiently guided to a specified location and direction, even when the existence of uncertainties and disturbances.
Design of Robustly Asymptotic Stabilizer Using a Time-Varying Sigmoid-Type SMC Scheme
(2008)
Liang, Yew-Wen
;
Xu, Sheng-Dong
;
Cheng, Chiz-Chung
;
Liaw, Der-Cherng
;
電控工程研究所
This study presents a class of first-order sliding mode stabilizing control laws, which preserve the advantages of rapid response and robustness from the conventional sliding mode control (SMC) schemes. The presented SMC laws are continuous everywhere so that the chaffering characteristic of the sign-type SMC laws is greatly alleviated. This scheme is also shown to be able to mend the saturation-type SMC's weakness of only achieving uniformly ultimate boundedness performance to an asymptotic stability level.
LQG optimal control of discrete stochastic systems under parametric and noise uncertainties
(2006-05-01)
Hsiao, Feng-Hsiag
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Xu, Sheng-Dong
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Wu, Shih-Lin
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Lee, Gwo-Chuan
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電控工程研究所
In this paper, the linear-quadratic-Gaussian (LQG) optimal control problem is considered and a robust minimax controller composed of the Kalman filter and the optimal regulator is synthesized to guarantee the asymptotic stability of the discrete time-delay systems under both parametric uncertainties and uncertain noise covariances. Designed procedures are finally elaborated with an illustrative example. (c) 2006 The Franklin Institute. Published by Elsevier Ltd. All rights reserved.
Reliable control of nonlinear systems via variable structure scheme
(2006-10-01)
Liang, Yew-Wen
;
Xu, Sheng-Dong
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This study proposes a class of variable structure stabilizing laws which make the closed-loop system be capable of tolerating the abnormal operation of actuators within a pre-specified subset of actuators. The ranges of acceptable change in control gain magnitude that preserves system's stability are estimated for the whole set of actuators. These ranges are shown to be able to be made larger than those obtained by linear quadratic regulator (LQR) reliable design (Veillette, 1995, and Liang et al, 2000) by the choice of control parameters. Besides, this approach doesnot need the solution of Hamilton-Jacobi (HJ) equation or inequality, which is essential for optimal approaches such as LQR and H-infinity reliable designs. As a matter of fact, this approach can also relax the computational burden for solving the HJ equation or inequality.
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.
Robust stabilization of fuzzy control for nonlinear multiple time-delay interconnected systems via neural-network-based approach
(2006)
Hsiao, Feng-Hsiag
;
Liang, Yew-Wen
;
Xu, Sheng-Dong
;
Lin, Chia-Yen
;
Tsai, Zhi-Ren
The stabilization problem is considered in this study for a nonlinear multiple time-delay large-scale (NMTDLS) system. First, the NN model is employed to approximate each subsystem. Then, an LDI state-space representation is established for the dynamics of each NN model. According to the LDI state-space representation, a robustness design of fuzzy control is proposed to overcome the effect of modeling errors between subsystems and NN models. Next, in terms of Lyapunov\'s direct method, a delay-dependent stability criterion is derived to guarantee the asymptotic stability of NMTDLS systems. Subsequently, a set of fuzzy controllers is synthesized to stabilize the NMTDLS system.
Robustness design of fuzzy control for nonlinear multiple time-delay large-scale systems via neural-network-based approach
(2008-02-01)
Hsiao, Feng-Hsiag
;
Xu, Sheng-Dong
;
Lin, Chia-Yen
;
Tsai, Zhi-Ren
;
電控工程研究所
The stabilization problem is considered in this correspondence for a nonlinear multiple time-delay large-scale system. First, the neural-network (NN) model is employed to approximate each subsystem. Then, a linear differential inclusion (LDI) state-space representation is established for the dynamics of each NN model. According to the LDI state-space representation, a robustness design of fuzzy control is proposed to overcome the effect of modeling errors between subsystems and NN models. Next, in terms of Lyapunov's direct method, a delay-dependent stability criterion is derived to guarantee the asymptotic stability of nonlinear multiple time-delay large-scale systems. Finally, based on this criterion and the decentralized control scheme, a set of fuzzy controllers is synthesized to stabilize the nonlinear multiple time-delay large-scale system.
Study of VSC reliable designs with application to spacecraft attitude stabilization
(2007-03-01)
Liang, Yew-Wen
;
Xu, Sheng-Dong
;
Tsai, Che-Lun
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This brief investigates variable structure reliable control (VSRC) issues of a set of second-order nonlinear systems and their application to spacecraft attitude stabilization. Both passive and active reliable designs are presented. To achieve the active task, an observer to identify faults as they occur in the spacecraft actuators is also presented. These VSRC laws do not require the solution of a Hamilton-Jacobi (HJ) equation, which is essential in the optimal approaches such as linear quadratic Riccati (LQR) and H-infinity reliable designs. As a matter of fact, this approach can relax the computational burden for solving the HJ equation. Simulation results regarding spacecraft attitude stabilization with comparisons among the VSRCs and the LQR reliable designs are also given. It is shown from these simulations that the active VSRC is the most flexible, robust and effective method because it does not need to prespecify susceptible actuators and because it allows more space for the control parameter adjustment.
T-S Model-Based SMC Reliable Design for a Class of Nonlinear Control Systems
(2009-09-01)
Liang, Yew-Wen
;
Xu, Sheng-Dong
;
Ting, Li-Wei
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This paper studies the robust reliable control issues based on the Takagi-Sugeno (T-S) fuzzy system modeling method and the sliding-mode control (SMC) technique. The combined scheme is shown to have the merits of both approaches. It not only alleviates the online computational burden by using the T-S fuzzy model to implement the original nonlinear system (since most of the system parameters of the T-S model can be offline computed) but also preserves the advantages of the SMC schemes, including rapid response and robustness. Moreover, the combined scheme does not require online computation of any nonlinear term of the original dynamics, and the increase in the partition number of the region of premise variables does not create extra online computational burdens for the scheme. Under the design, the control mission can continue safely without prompt external support, even when some of the actuators fail to operate. Meanwhile, both the active and the passive reliable designs are presented. The proposed analytical results are also applied to the attitude control of a spacecraft. 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.