Piecewise fault estimation observer design for discrete-time Takagi-Sugeno fuzzy systems

This paper studies the problem of robust fault estimation (FE) observer design for discrete-time Takagi-Sugeno (T-S) fuzzy systems via piecewise Lyapunov functions. The objective of this paper is to present a framework of the FE observer with less conservatism. First, under the multiconstrained design, an augmented FE observer (AFEO) is proposed to achieve FE for discrete-time T-S fuzzy models. Furthermore, based on the property of piecewise Lyapunov functions, an improved result on the AFEO is derived by introducing slack variables to reduce conservatism caused by the conventional multiconstrained design. Finally, simulation results are presented to illustrate the effectiveness of the proposed method.