Delay-dependent robust fault detection for a class of nonlinear time-delay systems

In this paper, the robust fault detection filter (RFDF) design problem is investigated for a class of nonlinear time-delay systems with unknown inputs. Firstly, a reference residual model is introduced to formulate the robust fault detection filter design problem as an H_infin optimization control problem. The reference residual model designed according to the performance index is an optimal residual generator, which takes into account the robustness against disturbances and sensitivity to faults simultaneously. Then, applying robust H_infin optimization control technique, the novel criteria of the robust fault detection filter for a class of nonlinear time-delay systems with unknown inputs is presented in terms of linear matrix inequality (LMI), which depends on the size of time delays. Finally, a numerical example is used to demonstrate the feasibility of our proposed method.