Actuator fault detection and reconstruction for nonlinear systems

Abstract:

Abstract: In this paper, the problems of the actuator fault detection and reconstruction based on observers are discussed for uncertain nonlinear systems, when the observer matching condition is not satisfied. An auxiliary output vector is introduced so that the observer matching condition is satisfied. A high-order sliding mode observer is considered to get the exact estimates of both the auxiliary outputs and their derivatives in a finite time based on the system measured outputs. A kind of fault reconstruction method based on the high-order sliding mode observer is developed. In the design, the Lipschitz constant can be unknown because an adaptive controller is implemented to adjust it adaptively. Finally, a numerical simulation example is given to illustrate the effectiveness of the proposed methods.