SENSOR FAULT DIAGNOSIS BASED ON A H∞ SLIDING MODE AND UNKNOWN INPUT OBSERVER FOR TAKAGI-SUGENO SYSTEMS WITH UNCERTAIN PREMISE VARIABLES

This paper presents the design of a H-infinity sliding mode and an unknown input observer for Takagi-Sugeno (TS) systems. Contrary to the common approaches reported in the literature, which considers exact premise variables, this work deals with the problem of inexact measurements of the premise variables. The proposed method is based on a H-infinity criteria to be robust to disturbances, sensor noise and uncertainty on the premise variables. The observer convergence and stability are established by considering a quadratic Lyapunov function, which relies on a set of Linear Matrix Inequalities. Then, a dedicated observer scheme is considered to detect and isolate sensor faults. Finally, the performance and applicability of the proposed approach are illustrated through numerical experiments on a nonlinear model that represents the lateral dynamics of an electric vehicle.