Research On Several Kinds Of Event-Driven Networked Control Systems

In recent years,with the extensive use of the computer communication network and the continuous development of the network technology,the research on networked control systems(NCSs)has been greatly advanced.However,due to the limited network bandwidth and computing resources in NCSs,the traditional periodical sampling will result in the unnecessary waste of computing resources.Therefore,it is necessary to design a reasonable event-triggered mechanism(ETM)for control systems in order to make rational use of the network bandwidth in NCSs.However,in the process of introducing the event-triggered mechanism into NCSs,problems such as the networked induced delay,actuator or sensor failure,packet loss and so on will be encountered.NCSs based on the event-triggered mechanism will produce instability or show poor performance.Therefore,in order to avoid these constraints,it is necessary to study event-driven networked control systems.The detailed research work of this paper is as follows:Firstly,LTI(Linear-time Invariant)systems based on the event-triggered mechanism are proposed for NCSs with time-varying delays.On the basis of LTI systems with the event-triggered mechanism and quantification,a quantitative observer is designed to observe the state of the system.By using the method of Lyapunov functional,sufficient conditions for the stability of the system are obtained,and the effectiveness of the results is proved by a simulation example.Secondly,on the basis of considering time-varying time delays and signal quantification,the NCS model including time-varying time delays and quantitative output feedback control is established.Based on this model,the event-triggered mechanism which can change the triggered frequency is introduced to obtain the closed-loop model which includes the event-triggered mechanism and the quantitative output feedback.Based on it,the reference tracking signal is given,and the error system is obtained between the reference signal and the networked model.By using the Lyapunov stability theory and linear matrix inequality method,the system is asymptotically stable and satisfies theH_?performance index in the mean square sense.Simulation results show that the system has good tracking performance and lower triggered frequency.Then,the problem of the event-triggered fault detection filter(FDF)and the controller coordination design for NCSs with the continuous time of failure is studied.By synthetically considering the network-induced delay and packet loss problem in NCSs,a closed-loop model including the event-triggered mechanism and FDF is established.For the integral inequality of vectors,the method of Jensen's inequality is used.Compared with the existing method of Wirtinger inequality,this method is not very conservative.The designed FDF and the controller can ensure the sensitivity of the remaining signal to the fault.The simulation results verify the effectiveness of the proposed event-triggered mechanism.Finally,the dynamic output feedback control(DOFC)of networked control systems based on the event-triggered mechanism is studied.By considering problems of the network induced delay and the timing disorder in NCSs,a closed-loop model including the event-triggered mechanism and DOFC is established.By Lyapunov functional,the stability criterion is given combined with mutually exclusive distribution and Jensen's inequality.