Observer-based integrated robust fault estimation and accommodation design for discrete-time systems

Abstract

In this article, a challenging issue on observer-based integrated robust fault estimation and accommodation for a class of discrete-time uncertain nonlinear systems is studied. First, a multiobjective augmented fault estimation observer (AFEO) containing an α-exponential stability performance index and an H ∞ performance index is proposed not only to guarantee the convergence speed of fault estimation but also to restrict the influence of uncertainties with respect to the fault estimation error as much as possible. Then, by introducing a slack matrix, new results are obtained to reduce the conservatism generated by the conventional multiobjective design method. Furthermore, a robust fault tolerant controller based on the dynamic output feedback is designed to guarantee the stability of the closed-loop system in the presence of faults. Moreover, the AFEO and the dynamic output feedback fault tolerant controller (DOFFTC) are designed separately and their performances are considered respectively. Finally, the simulation results of a practical system are presented to illustrate the effectiveness of the proposed design techniques.