Robust H∞ fault estimation and fault tolerant control for T-S nonlinear systems with time varying delays

Abstract

This paper investigates the fault estimation and fault tolerant control (FTC) for discrete time nonlinear system with multiple bounded state delay using the Takagi-Sugeno (T-S) fuzzy model. First, a fuzzy-fault estimation observer (FFEO) design is proposed to achieve fault estimation of T-S models with actuator faults. Based on the information of online fault estimation, a state feedback-fault tolerant controller (SFFTC) using the estimate of state is designed to compensate the effect of faults by stabilizing the closed-loop system. The disturbance rejection attenuation is constrained to a given level using a Hœ-performance index. Sufficient conditions are established for the existence of the desired (FFEO) and (SFFTC) in terms of linear-matrix inequalities (LMIs). An example is given to illustrate the effectiveness and applicability of the proposed method.