Fault detection for switched systems with all modes unstable based on interval observer

Abstract This paper concentrates on observer-based fault detection (FD) for switched systems. By the introduction of the interval observer, the error dynamic system is proposed. In light of the switching logic, exponential stability of the augmented system is firstly achieved. Then, to ensure the fault sensitivity as well as disturbance robustness, H∞/ H − performance analysis is employed. One thing has to be mentioned is that we investigate the unobservable condition of (Ai; Ci). Moreover, the instability of the error dynamic system brought by the unobservability is eliminated by the switching strategy using average dwell time (ADT) method. Afterwards, sufficient conditions guaranteing the H∞/ H − performance level are obtained, which is divided into disturbance attenuation and fault sensitivity analysis. Finally, examples demonstrating the effectiveness of the provided method are provided.