Robust fault detection filter design for uncertain switched systems with adaptive threshold setting

In this paper, the fault detection (FD) problem of uncertain discrete-time switched systems under the constrained switching law and external disturbances is addressed. In the multiple Lyapunov functions (MLF) framework with ℋ-/ℋ_∞ performance index, a robust fault detection filter (RFDF) is designed in order to generate a residual signal which is sensitive to the faults and robust against the disturbances. The design method is formulated to be solved by linear matrix inequality (LMI) technique. The main contribution in this paper is to improve the performance of the FD for switched systems by considering switch detection logics. The design of the RFDF is based on the local performance index of each subsystem. An adaptive threshold is set based on both, the bounds of disturbances and the individual performance index for each subsystem.