Adaptive Fault-Tolerant Control Of Nonlinear Switched Systems Based On Event-Triggered

As an important class of hybrid systems,switched systems are used to describe many practical systems with switching characteristics.In terms of controller design and stability analysis,compared with single nonlinear system that only deals with the internal dynamic characteristics of systems,switched nonlinear systems also need to consider the relationship between each subsystems.How to design controllers and switching rules to ensure the stability of systems is one of the research focuses of control theory.The con-trol idea based on switching and the control technology of multiple controllers switching are also widely used in control theories and control engineering practice.At the same time,how to save limited resources under the premise of ensuring systems’control per-formance has become an important problem.The mechanism of event-triggered control has been proposed,which obviously saves resources and is rapidly applied.In the pro-cess of systems operation,the occurrence of actuator faults is inevitable.In practice,the occurrence of faults will reduce the performance of systems,even destroy the stability of systems,which will cause serious accidents.The emergence of adaptive fault-tolerant control can ensure that systems in failure remain stable and have ideal performance.In this thesis,the fault-tolerant control of nonlinear switched systems is discussed based on event-triggered strategy,adaptive control,H_∞technology and backstepping technique.The main research contents of this thesis are as follows:The second chapter considers theH_∞adaptive fault-tolerant control of nonlinear switched systems based on event-triggered strategy.In this chapter,aH_∞adaptive fault-tolerant controller and a parameter adaptive update law are constructed,which can ef-fectively compensate the influence of actuator faults and parameter uncertainties.The event-triggered strategy based on fixed threshold method is applied to theH_∞adaptive fault-tolerant controller.Combined with Lyapunov stability theory,the matrix inequality conditions for the stability of the closed-loop systems are given,and the effectiveness of the control scheme proposed in this chapter is verified through simulations.In chapter 3,the problem of event-triggered adaptive fault-tolerant control is consid-ered for a class of nonlinear switched systems with unknown control coefficients and state constraints.The switched barrier Lyapunov function is used to compensate the influence of state constraints,and the lower bound of unknown control coefficients is introduced to counteract the influence of unknown control coefficients.Virtual controller and adap-tive update law are constructed by Backstepping method to compensate actuator faults.The designed scheme effectively reduces the communication burden,ensures the bound-edness of all signals of the closed-loop switching system and the boundedness of the tracking error.Two simulation examples show that the method proposed in this chapter is effective.Finally,the main work of this thesis is summarized and the future research directions are prospected.