Fault-tolerant Control For Nonlinear System Based On Fault Diagnosis Observer

The issue about system security and reliability must be solved by all both controltheorists and system engineers, the research on fault diagnosis and fault-tolerant controlprovides a new direction to solve the problem. Considering the nonlinearity is widespreadin many systems, and the study of nonlinear systems has also been difficult. In this paper,the study on fault-tolerant control for nonlinear system based on fault diagnosis wasaddressed. The main contributions of this paper are as follows:1) The fault-tolerant H_∞control problem for a class of nonlinear neutral systems whichnonlinearity satisfies Lipschitz condition is studied in Chapter Two. The purpose of thischapter is to construct the appropriate fault diagnosis observer to get the information offault. Then design the fault-tolerant controller. The sufficient condition of guarantee thestability of system in case of failure and approach of design fault-tolerant H_∞controllerwas derived. Finally, a numerical example is proposed to show the method is reasonable.2) The problem of fault-tolerant control design for nonlinear system based on adaptiverobust observer is presented in Chapter Three. The aim of the research is to design afault-tolerant controller to make the system is stable after fault occurs based on faultinformation that is obtained from the design adaptive robust observer. The constitution ofadaptive law of adaptive robust observer is given and the sufficient condition for existenceof the designed fault-tolerant controller is derived in the form of LMI. At last, Thesimulation result is showed to demonstrate the feasibility and effectiveness of the posedapproach.3) The fault-tolerant control problem is considered for a class of uncertain systemsbased on output feedback in Chapter Four. The goal of study is to design a fault-tolerantcontroller on the basis of output feedback to guarantee the closed-loop system is robuststable and satisfy the given performance index when the actuators and sensors of systemare all failure or one of them failure. The sufficient condition for existence of fault-tolerantcontroller in the framework of linear matrix inequality theory was derived. Accordingly,the simulation example is given to illustrate the feasibility of the method.