Improved robust reduced-order sliding mode fault-tolerant control for T-S fuzzy systems with disturbances

Abstract

This work investigates the problem of robust sliding mode fault-tolerant control for Takagi-Sugeno (T-S) fuzzy systems with disturbances. By virtue of a nonlinear sliding variable with an exponential decaying term, a reduced-order fuzzy sliding motion is established for the system throughout the entire responses. Since the existence of unforeseen actuator faults and disturbances affects the transient performance of sliding variable, which leads to poor performance of sliding motion system. To mitigate the influences of faults and disturbances on the sliding motion system, a class of positive semi-definite barrier functions is introduced to design controller, which ensures the sliding variable within a prescribed upper bound independent to actuator faults and disturbances. Finally, through the Lyapunov direct method, some sufficient conditions are derived such that the closed-loop system is uniformly bounded with time-vary performance boundary. In simulation part, several examples are given to demonstrate the effectiveness of the theoretical results.