Adaptive Control For Several Classes Of Nonlinear Systems

With the rapid development of science and technology,the systems that need to be controlled are becoming more and more complex,and people's requirements for control performance are getting higher and higher,so non-linear systems play an increasingly important role.In the face of complex practical problems,it is usually difficult to describe them with mathematical models accurately.There may be uncertainties or constantly changing parameters in the models,so the application of adaptive control in the system is a good solution in the controller design.This thesis discusses the adaptive control for several different types of nonlinear systems.The main innovation of this paper is to discuss the application of adaptive control in the theory or several kinds of nonlinear systems with practical background significance,such as the application in Fault Tolerant Control or the application in the model of infectious disease transmission among animals with economic value,the model of highly non-linear anaerobic digestion system of biomass,the six-degree-of-freedom trajectory model.At present,there are few practical problems to be solved by applying relevant theories.It has certain theoretical and practical application value to provide reference for its practical application.In the second chapter,the control problem of a class of singular systems with time-delay is studied.A class of nonlinear singular systems with time-delay is established by considering economic benefits.The tracking control problem of the system is discussed by using Lyapunov's theorem with scaling method,feedback method and adaptive control law.In the third chapter,a mathematical model of biomass anaerobic digestion system is introduced,which is characterized by complex model,many parameters and highly non-linear system.To solve this problem,sliding mode function and neural network are designed to approximate the corresponding unknown non-linear function to solve the control problem of the system.Through the study of the problem,it can provide a reference for the control research of biomass anaerobic digestion model by means of the powerful computer computing power.In the fourth chapter,For a special kind of actuator failure,i.e.the loss of system control input but not complete failure,the standby scheme can be given in advance when designing the controller.The method is to ensure the stability of the system by estimating the loss value and utilizing the principle of adaptive control.This is an emergency solution for some systems with high performance requirements in case of inconvenience and timely maintenance.In the fifth chapter,the control problem of a kind of six-degree-of-freedom trajectory model is discussed.The model is transformed into two parts: the part of determining parameters and the part with unknown parameters,and the controller is designed by adaptive control and other related theories to ensure the feasibility of tracking control of the system,which provides a new idea for the study of six-degree-of-freedom trajectory model.