H∞ sensor faults estimation for T-S models using descriptor techniques: Application to fault diagnosis

This paper deals with the H infin estimation of both system state and faults for T-S (Takagi-Sugeno) fuzzy model with bounded input disturbances. Based on the descriptor technique, the sensor faults are considered as an auxiliary state variable. Then a descriptor observer for the obtained augmented system is designed and the observer gains are determined in LMI (Linear Matrix Inequalities) formulation. This method has the advantage to estimate the state variables and the sensor faults simultaneously with H infin approach. Numerical example shows the efficiency of the proposed method.