A quadratic boundedness approach to fault tolerant control for nonlinear system

Abstract

In the paper, a methodology of actuator fault estimation and fault tolerant control for nonlinear systems is proposed. To solve such a challenging problem, a quadratic boundedness (QB) approach is used to design observer in such a way that the state and fault estimation error will converge to the origin (as close as possible) irrespective of the external disturbances. The same approach (QB) is used to design fault tolerant control to compensate the effect of an actuator fault in system, which is suitably integrated with state and fault estimation schemes. Sufficient conditions for the existence and stability of the proposed state and fault estimation scheme as well as the fault tolerant control are expressed in the form of linear matrix inequalities (LMIs). To show effectiveness of the proposed approach, the final part of the paper presents simulation results concerning a quadruple–tank system.