Research And Application Of Network Control System

With the continuous development of computer and network technology,various components in the control system are interconnected using the communication network,which has become the main development trend of the control system in the future.This study focuses on the problem of time-varying sampling period and packet loss in networked control systems,combining Lyapunov stability theory,LMI method,comprehensive Schur complement lemma,Markov chain jump system theory and other diversified mathematical tools to study NCS.Model establishment,controller design and other aspects.The main research content includes:Firstly,for the network control system with time-varying sampling period and random packet loss,the design of the robust controller is analyzed.After this,a standardized discrete-time dynamic model of NCS is established.This model describes the characteristics of NCS data packet loss through the Bernoulli distribution sequence,and performs the time-varying of the sampling period and transmission delay of NCS through the uncertainty interval matrix.description.Under this premise,necessary conditions for the existence of robust controllers for asymptotically stable closed-loop systems are given.The developed controller ensures that the system is asymptotically stable and that it exhibits a certain level of disturbance rejection.Secondly,for the two cases of short delay and long delay,the analysis system has the stabilization problem corresponding to both random induction delay and asynchronous packet loss characteristics.Then,the uncertainty of the network delay is transformed into the uncertainty of the system parameters.After that,the system is modeled as an asynchronous independent dynamic system with two time-rate constraints.Combining with the theory of asynchronous dynamic system,the sufficient criterion of exponential stability under system state feedback and dynamic output feedback and the corresponding controller design method are given.After that,the LMI is used to represent it concretely.Thirdly,in order to deeply analyze the packet loss characteristics of the data,we analyze the random time-varying delay and the robust control of NCS state feedback with Markov jump characteristic data packet loss.Thus,the uncertainty of the network delay is transformed into the uncertainty of the system parameters,and the network control system is modeled as a Markov jump system including two modes.According to the Markov jump system theory,the necessary conditions for the existence of robust controllers for system state feedback are given by the LMI method.Finally,the characteristics of the distillation tower control in petrochemical industry are analyzed,and the network control is connected with the temperature control of the distillation tower.The design method with random induction delay and asynchronous packet loss NCS given in this study was applied,after which the feasibility was simulated and analyzed.This part is the specific application of NCS to practical problems.The research results of this paper have been carried out by numerical examples and simulation studies.The results obtained show that the research content has ideal feasibility and effectiveness.