Reduced-order fault detection filter design for switched nonlinear systems with time delay

This paper investigates the problem of reduced-order robust fault detection filter (RFDF) design for a class of switched nonlinear systems with time-varying delay. The nonlinearities are assumed to satisfy global Lipschitz conditions. By using a generalized form of observer-based fault detection filter as a residual generator, the problem is formulated in the framework of H _∞ filtering. Based on the average dwell time approach and the Lyapunov functional technique, a sufficient delay-dependent criterion on the existence of the RFDF is derived to ensure the exponential stability and a prescribed L ₂-gain bound of the residual error system. Furthermore, the parameters of an admissible filter are obtained from the solution of a convex optimization problem. A practical example is provided to illustrate the effectiveness of the proposed results.