Adaptive Dynamic Surface Control Design Of MIMO Switched Nonlinear Systems And Its Application

With the increasing complexity of modern industrial production,its control system performance requirements are becoming higher and higher,the traditional linear control theory and methods have been difficult to meet various practical requirements,the importance of nonlinear control has become increasingly prominent.This is because physical conditions in practice are constrained by a variety of constraints,such as input constraints in many practical systems is very common.Therefore,the problem of input saturation of nonlinear systems has become a very important research topic.On one hand,as a special hybrid system,switched systems have attracted much attention in the past few decades.The reason is that many practical systems need to be modeled as switched systems,such as transportation systems,power systems and mechanical systems.On the other hand,network control has been applied to more and more fields in the current society.It can not only improve control accuracy,but also effectively reduce costs.However,the use of network control may lead to the problem of communication bandwidth waste,the event-triggered control strategy can effectively reduce the network control of communication bandwidth occupancy.Using switched systems theory,dynamic surface control technique and backstepping,it is a feasible way to study the adaptive control problem of switched nonlinear systems.But,there are few reports about the mentioned issue above in the existing literature.In this thesis,the problem of adaptive tracking control under arbitrary switching and event-triggered adaptive tracking control with minimum dwell time for MIMO switched nonlinear systems with input constraints and external disturbances are studied.The details are as follows:First,the adaptive dynamic surface control problem of MIMO switched nonlinear systems with input saturation and external disturbance is studied under arbitrary switching.Based on backstepping,a disturbance observer is designed to estimate the external disturbance,a switched auxiliary system is constructed to deal with the input saturation problem,and a switched dynamic surface control technique is used to deal with the"computational expansion" problem of the virtual controller in the process of derivation by backstepping.By using the common Lyapunov function method,all signals in the closed-loop system are semi-globally uniformly bounded under arbitrary switching.At the same time,the tracking error of the system converges to a compact set.The proposed control design method is applied to the variable structure near space vehicle model to illustrate its effectiveness.Second,for the case of input saturation and external disturbance,the problem of event-triggered adaptive trajectory tracking control for MIMO nonlinear systems is studied.Based on backstepping,a Nussbaum disturbance observer is designed to estimate the external disturbance,and an auxiliary system is constructed to deal with the input saturation problem.The dynamic surface control technique is used to deal with the "computational expansion"problem of the virtual controller in the process of derivation by backstepping.A new controller is designed and the Lyapunov function method is used to ensure that all signals in the closed-loop system are semi-globally uniformly bounded.Also,the Zeno phenomenon during the event triggering is avoided.The proposed control design method is applied to the near space vehicle model to illustrate its effectiveness.Third,in the case of input saturation and external disturbance,the problem of event-triggered adaptive dynamic surface control for MIMO switched systems with minimum dwell time is studied.On the basis of the controller designed in the first part,combined with the switching rule and the event triggering condition in the second part,the controller is redesigned to ensure that all signals in the closed-loop system are semi-globally uniformly bounded,and the tracking error of the system converges to a compact set.Also,the Zeno phenomenon during the event triggering is avoided.Then the proposed control design method is applied to the variable structure near space vehicle model to illustrate its effectiveness.The conclusions and perspectives are presented in the end of the thesis.