Browsing by Author "Xu, SD"

Now showing 1 - 6 of 6

Application and robustness design of fuzzy controller for resonant and chaotic systems with external disturbance
(2005-06-01)
Hsiao, FH
;
Chiang, WL
;
Chen, CW
;
Xu, SD
;
Wu, SL
A robustness design of fuzzy control via model-based approach is proposed in this paper to overcome the effect of approximation error between nonlinear system and Takagi-Sugcno (T-S) fuzzy model. T-S fuzz model is used to model the resonant and chaotic systems and the parallel distributed compensation (PDC) is employed to determine structures of fuzzy controllers. Linear matrix inequality (LMI) based design problems are utilized to find common definite matrices P and feedback gains K satisfying stability conditions derived in terms of Lyapunov direct method. Finally, the effectiveness and the feasibility of the proposed controller design method is demonstrated through numerical simulations on the chaotic and resonant systems
Application of VSC reliable design to spacecraft attitude tracking
(2005)
Liang, YW
;
Xu, SD
;
Chu, TC
;
Cheng, CC
;
Liaw, DC
This study investigates variable structure reliable control issues of nonlinear systems and its applications to spacecraft attitude tracking problems. The proposed passive reliable control laws must know in advance which group of actuators is allowed to fail. These reliable controllers need not the solution of Hamilton-Jacobi (HJ) equation or inequality that are essentials in optimal approaches such as LQR and Hoo reliable designs. As a matter of fact, this approach is able to relax the computational load in computing the solution of HJ equation. 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 Variable Structure Control (VSC) reliable designs are presented to illustrate the merits of the proposed scheme. Although the proposed design is a passive one, it may provide a guideline for active design when a Fault Detection and Diagnosis (FDD) scheme is available.
On existence and construction of stabilizing switching laws between two unstable linear systems
(2005)
Liang, YW
;
Tan, YH
;
Xu, SD
;
Chang, JL
;
電控工程研究所
Issues regarding the application of two equivalent sufficient conditions for the existence of stabilizing switching laws between two unstable linear systems are studied. One of the conditions is effective for theoretical derivation, while the other is easily implementable. To further understand the geometrical insight of the conditions, an equivalent condition involving the information of eigenvalues and eigenvectors of system dynamics is presented for planar cases. With the help of the equivalent relation, a condition for the existence of controllers and stabilizing switching laws between two unstabilizable linear control systems is also presented. The controllers and stabilizing switching laws are explicitly constructed through the use of an existed algorithm.
Reliable output tracking control for a class of nonlinear systems
(2004-09-01)
Liang, YW
;
Xu, SD
;
Chu, TC
;
Cheng, CC
;
電控工程研究所
This study investigates nonlinear reliable output tracking control issues. Both passive and active reliable control laws are proposed using Variable Structure Control technique. These reliable laws need not the solution of Hamilton-Jacobi (HJ) equation or inequality, which are essential for optimal approaches such as LQR and H-infinity reliable designs. As a matter of fact, this approach is able to relax the computational burden for solving the HJ equation. The proposed reliable designs are also applied to a bank-to-turn missile system to illustrate their benefits.
T-S fuzzy controllers for Nonlinear interconnected systems with multiple time delays
(2005-09-01)
Hsiao, FH
;
Chen, CW
;
Liang, YW
;
Xu, SD
;
Chiang, WL
This paper investigates the effectiveness of a passive tuned mass damper (TMD) and fuzzy controller in reducing the structural responses subject to the external force. In general, TMD is good for linear systems. We proposed here an approach of Takagi-Sugeno (T-S) fuzzy controller to deal with the nonlinear system. To overcome the effect of modeling error between nonlinear multiple time-delay systems and T-S fuzzy models, a robustness design of fuzzy control via model-based approach is proposed in this paper. A stability criterion in terms of Lyapunov's direct method is derived to guarantee the stability of nonlinear multiple time-delay interconnected systems. Based on the decentralized control scheme and this criterion, a set of model-based fuzzy controllers is then synthesized via the technique of parallel distributed compensation (PDC) to stabilize the nonlinear multiple time-delay interconnected system and the HI control performance is achieved at the same time. Finally, the proposed methodology is illustrated by an example of a nonlinear TMD system.
Voltage collapse detection of a power system based on the FIDF technique
(2005)
Liang, YW
;
Liu, HY
;
Xu, SD
;
Lin, SJ
;
電控工程研究所
In this paper, an effective linear-based fault identification filter (FIDF) design technique is applied to voltage collapse detection in a power system so that a corrective action can be made at the onset of unstable phenomena. This is achieved by treating the difference between the load voltage of the power system and that of its linearized model at a stable operating point as a fault vector and then investigating the effect of the fault on the designed FIDE. In practical applications, since FIDF has a low pass filter property and is easily calculated, it can effectively attenuate the influences of high frequency measurement noises and be employed as an on-line detection scheme. Simulation results for Dobson and Chiang's power system model (1990) are finally given to demonstrate the effectiveness of the FIDE design.