Fault Diagnosis for Time-delay Systems Based on Delay-dependent H_∞ Filter

A robust fault detection (RFD) scheme is proposed for a class of time-delay systems with uncertainty inputs. The fault detection filter is designed by using H_∞ control theory. The reference model is introduced to formulate the generalized residual, and the robustness of residual to unknown inputs and the sensitivity to fault signal are reflected by an L_2-gain. By using the dual principle and linear matrix inequality (LMI) approach, the design of observer-based RFD system is proposed. The existence condition and the solution of observer gain matrix, which are dependent on the size of the delay, are also given. Finally, an example is given to demonstrate the effectiveness of the proposed approach.