The Research On Event Triggered Control Of Cyber-Physical Systems

Cyber physical system(CPS)is a closed-loop control system which integrates computer technology,network communication technology and control technology.It realizes information interaction and intelligent coordinated control between information space and physical space,and is widely used in many important fields.CPS transmits data information through commu-nication network.However,the introduction of communication network makes data sharing faster and more efficient,and also brings great communication burden to the network.In order to prevent packet loss and system instability caused by network congestion,more and more scholars pay attention to the communication control of CPS.The event triggering mechanism is introduced into the control system,which can effectively solve the above problems by reducing the transmission amount of communication network packets and saving the limited network bandwidth.In recent years,many achievements have been made in the research of CPS event triggered control,but most of the existing achievements are limited to considering only the introduction of event triggers into the sensor controller channel,thus ignoring the network resource utilization of the controller actuator channel.Secondly,the introduction of event triggered mechanism will reduce the conservatism of the system,so the coordinated design of event triggered mechanism and controller is particularly important.In order to make up for the above shortcomings,this paper takes CPS as the research object,from the perspective of communication and control problems,studies the closed-loop system model establishment,stability analysis and controller design based on two terminal event triggered control CPS.The details are as follows:First of all,the CPS is modeled as a continuous time linear system,and the dynamic output feedback control problem of CPS based on discrete event triggering is studied.At the same time,discrete event triggering strategy is introduced into sensor controller and controller actuator channels to reduce the amount of data transmission by expanding the event interval.In order to ensure the stability of the closed-loop system,the sufficient conditions for the asymptotic stability of the system are obtained by using Lyapunov stability theory.The cooperative design of the two terminal event trigger parameters and the dofc is realized to ensure the desired control performance of the system.The event trigger mechanism is implemented asynchronously in sensor nodes and controller nodes.Finally,an example is given to illustrate the effectiveness of the proposed method.Secondly,CPS dynamic output feedback with two terminal dynamic event triggering strategy is studied H_?control problem.Firstly,the closed-loop system is modeled as a linear system with two interval time-varying delays.The internal dynamic variables are introduced into the event triggering strategies of sensor controller and controller actuator channels respectively,and the CPS communication mechanism based on asynchronous dynamic event triggering strategy is established.By expanding the event interval,the amount of data transmission in the two channels is reduced.Secondly,considering the time delays of sensor controller and controller actuator channels,the H_?of the closed-loop system is studied by using Lyapunov Krasovskii functional,stability criterion of the closed-loop system is obtained.Based on this stability criterion,the cooperative design of dynamic output feedback controller and dynamic event triggering strategy is realized.In addition,the positive scalar lower bound of the minimum trigger time interval under the event trigger strategy is proved,which eliminates the zone phenomenon.Finally,an example of satellite system is given to illustrate the effectiveness of the proposed strategy.Finally,in order to further improve the utilization of network resources,the dynamic output feedback control problem of CPS with two terminal adaptive event trigger mechanism is studied to reduce the amount of data transmission and the network bandwidth burden.Firstly,the closed-loop system is modeled as a linear system with two interval time-varying delays,and adaptive event triggering mechanisms are proposed to establish a closed-loop control system with two terminal delays.Different from the discrete event trigger mechanism,the trigger threshold of adaptive event trigger mechanism depends on the state information of the latest release time and the current sampling time,and the threshold of trigger parameters can reach a fixed value through online adjustment.Secondly,by using Lyapunov Krasovskii functional method,the closed-loop system is asymptotically stable and satisfies the system H_?sufficisent conditions for the performance of the controller are obtained.A collaborative design method of gain matrix and event trigger mechanism parameters of dynamic output feedback controller is proposed.Finally,an example is given to illustrate the design method.