Event-triggered Tracking Control For Switched Systems

As a special class of hybrid system,the switched system has attracted more and more attention from scholars because of their theoretical knowledge and switched methods applied widely in the field of engineering.The tracking control of the switched system is one of the basic problems in control theory,among which the characteristics of the switch will increase the difficulty of tracking control.With the rapid development of computer technology,many practical engineering systems have adopted event-triggered control strategies in recent years.The basic idea of the event-triggered mechanism is a kind of control strategy that determines whether the controller is updated by designing appropriate triggered conditions based on the real-time state of the system.The triggered condition was designed to ensure a strict positive lower bound between two consecutive triggered intervals to avoid Zeno behavior.As a new sampling mechanism,when the system state changes relatively small,compared with the time triggered,event-triggered control can significantly reduce the amount of computation and thus improve the utilization rate of resources.Meanwhile,it can also make the controlled system have better performance in terms of stability performance.The periodic event-triggered mechanism combines conventional periodic sampling control and event-triggered mechanism.The system only needs to verify the driving conditions at a fixed sampling time and decide whether to transmit new sampling information.So far,the research on tracking control of nonlinear switching systems based on event-triggered strategy is very limited.In this thesis,event-triggered tracking control of nonlinear switched systems is studied respectively.The main research contents are summarized in the following two aspects:(1)Event-triggered tracking control of nonlinear switched systems is researched.Firstly,the system is transformed into an augmented system by designing an integral controller based on triggered conditions.Secondly,it is proved that the output tracking error of the closed-loop system can converge to a bounded region when the switched signal satisfies the average dwell time.Finally,Zeno behavior is successfully avoided during the sampling process by proving that the proposed minimum event interval always has a strictly positive lower bound.(2)The output tracking problem of nonlinear switched systems is studied based on the periodic event-triggered control mechanism.Firstly,based on the proposed periodic event-triggered mechanism strategy,an integral controller is designed,and the closed-loop system is modeled as a switched system with a delayed state.Secondly,considering the asynchronous switch between subsystem and controller,the relationship between dwell time and average dwell time is given.Finally,by constructing a class of the Lyapunov-Krasovskii function and introducing the free-weighting matrix method,sufficient conditions for solving the output tracking control problem of the closed-loop system are obtained.Finally,the work content of this thesis is summarized,and the following research direction is proposed.