Analysis And Design Of Networked Motor Control System Based On Two Side Closed-loop Function Method

With the rapid development of computer and network communication technology,networked control system(NCS)has received extensive attention.In networked control systems,sampling,as the front end of information processing,plays an important role in the process of network communication and data transmission.The speed of component execution and network bandwidth in the system are limited.Congestion will inevitably occur in signal acquisition and transmission,resulting in data transmission delay,and the delay is usually uncertain in the network environment.As we all know,increasing the sampling period can save network communication resources.Therefore,in the network environment with data transmission delay,the study of the relationship between the uncertain delay and the maximum sampling period to ensure the stability of the system has guiding significance for the design of practical networked control systems.Therefore,this paper mainly analyzes and designs the influence of uncertain time delay on Networked Control System in network environment.The main contents are as follows:Firstly,the mathematical model of networked AC asynchronous motor control system is established.In Simulink,the simulation model of networked asynchronous motor is built by using Truetime toolbox.The influence of time delay and external disturbance on the stability of the control system is analyzed by using PID control method.Secondly,when analyzing networked sampled data control systems,a new Lyapunov functional is constructed by using the bilateral closed-loop function method,and the asymptotic stability of sampled data systems with uncertain time delays is studied.In order to comprehensively consider the information of sampling period and transmission delay,in the process of processing the functional,the integral interval is divided into several sub intervals,and then the same integral interval is combined.Then the asymptotic stability criterion of the system is derived by using the free matrix integral inequality.Finally,a numerical example is given to illustrate the effectiveness of the method.Finally,the problem of sampling controller design in the network environment is studied.The nonlinear term in the process of solving the sampling controller is linearized,and the maximum sampling period and the corresponding controller K of the sampling control system in the case of time-delay uncertainty are obtained.Considering the fact that the aging,loss and other factors of AC asynchronous motor may lead to the uncertainty of motor parameters,the stability analysis is carried out considering the uncertainty when solving the networked asynchronous motor sampling controller.Based on the H_∞ control theory,a stability criterion about γ norm bound stability is obtained,and a linear matrix inequality condition satisfying the existence of the H_∞ controller is obtained.The effectiveness of the method is verified by numerical examples and simulations.