Robust Fault Detection Scheme for Asynchronous Switched Systems via Sliding Mode Observer

This work studies the fault detection problem for continuous-time asynchronous switched systems. For residual signal generation, we design a fault detection sliding mode observer such that residual characterizes the fault sensitivity level by H_ performance, and its robustness to process disturbance is determined by H(infinity )performance. Specifically, the challenge entails addressing the phenomenon of asynchronous switching between the controlled object and the observer, where there is a delay between the switching of the subsystems and the observer. A piece-wise Lyapunov function and average dwell time approach are applied to resolve the asynchronous switching stability within matched and unmatched periods. A feasible solution is derived based on linear matrix inequalities. For effective fault detection, a residual evaluation scheme is provided with a threshold. Finally, simulation results on a buck-boost converter are furnished to validate the usefulness of the proposed approach.