Robust fault estimation for Takagi-Sugeno fuzzy systems with interval nonlinear state time-varying delay

The research object of this paper is a nonlinear interval time-varying time-delay system with external disturbances, actuator and sensor faults based on T-S fuzzy model. A proportional integral observer is constructed to estimate the state, actuator and sensor faults simultaneously. Then, the Lyapunov function is constructed to analyze the stability of the system, and the delay dependent conclusion described by linear matrix inequality is obtained. The upper and lower bounds of interval time-varying delay are considered, which greatly reduces the conservatism of the conclusion, and the effect of fault estimation will be more accurate. Finally, the effectiveness of the proposed method is verified by a simulation example, that is, the designed observer can realize the simultaneous estimation of actuator and sensor faults, and meet the given H 8 performance index of the system.