Joint Observer Based Fault Tolerant Control for Discrete-Time Takagi-Sugeno Fuzzy Systems With Immeasurable Premise Variables

This article presents a robust observer-based fault-tolerant control for discrete-time Takagi-Sugeno (T-S) fuzzy systems where premise variables are unavailable. The augmented unknown input observer and optimization method jointly establish a robust state and fault estimator. Specifically, the estimation of the states provides rich information about the premise variables, which is essential for designing the fuzzy membership function of the fuzzy observer. Based on the estimation of faults, signal compensators are designed to attenuate the influences from actuator and sensor faults. The proposed observer-based fault-tolerant controller is compatible with a pre-existing controller of a nonlinear dynamic system. The stability and robustness of the closed-loop system after fault-tolerant control are addressed. Finally, the developed fuzzy observer-based fault-tolerant controller is demonstrated via a nonlinear rotary inverted pendulum.