Design of sliding mode observers for TS fuzzy systems with application to disturbance and actuator fault estimation

In this paper an observer-based fault detection approach for a class of nonlinear systems, which can be modeled by Takagi-Sugeno (TS) fuzzy models, is presented. We propose a sliding mode fuzzy observer that deals with unmeasurable premise variables, bounded uncertainties in the plant and allows fault estimation based on an equivalent output error injection approach. Necessary conditions for the existence of the robust observer are derived from sliding mode theory. Stability is ensured by linear matrix inequality (LMI) based sufficient conditions. An illustrative example demonstrates the effectiveness of the proposed scheme.