H_/H ∞ observer design for nonlinear T-S fuzzy systems subject to sensor and actuator faults

In this paper, the detection and estimation problem of sensor and actuator faults (SAF) for nonlinear systems represented by Takagi-Sugeno (T-S) fuzzy models subject to an Unknown Bounded Disturbance (UBD) is investigated. Moreover, we focus on state estimation. For this, we propose a new observer design to simultaneously estimate state and SAF vectors. This observer not only lead to estimate the actuator fault, but also to improve the performance of fault estimation. To maximize the fault effects on the residual and minimize the disturbance effects, we consider the H_/H ∞ performances. For the stability, conditions are given in term of Linear Matrix Inequalities (LMIs). Finally, simulation results are afforded to prove the mentioned process efficiency.