Robust fault detection for nonlinear systems based on observer

In this paper, the problem of observer-based robust fault detection is studied for T-S fuzzy systems. A T-S model described fuzzy observer is considered as a fault detection filter to generate residual. The problem of fault detection is formulated into a model-matching problem so that the influence of uncertainty and disturbance is minimized to increase the robustness of residual to unknown inputs, while the effect of fault is maximized to enhance the sensitivity to fault. By using the H_∞ optimization technology, a solvable sufficient condition is derived and the observer gain matrix can be solved in terms of LMIs.