Study On Synchronization And Control For Quantized Feedback Systems

In practical engineering applications,due to the rapid development of the communication technology and the continuous improvement of control systems performance,the control systems contain more and more sensors,controllers,actuators and other components,which leads to the increasing scale of control systems.As a result,more and more control systems choose the network to connect various components.This type of system that transmits information over a real-time network is called network systems.Compared with traditional point-to-point systems,the network systems have the advantages of resource sharing,remote operation,low cost,and easy maintenance.However,the introduction of network control systems also brings some new problems,such as the signal quantization,the packet loss,and the signal transmission delay.Because there are usually some quantization errors after quantizing the signal,this may cause systems performance degradation or even systems instability.Therefore,signal quantization is an important issue to be solved.Moreover,there may be influences of the random noise,the time delay and the nonlinearity in control systems,which makes the study of control systems very complicated.Therefore,this article focuses on the nonideal conditions such as the random noise,the time delay and the nonlinearity that may exist in control systems.For different quantization feedback systems,the synchronization and stability are studied.Finally,the quantized control method designed in this paper is applied to the DC motor system.By designing the adjustment scheme of dynamic quantization parameters to make the DC motor system asymptotically stable,it can also achieve the corresponding H_?noise attenuation level.The simulation results show that the control effect is good.The main achievements of this paper are as follows.1)The exponential synchronization problem of chaotic systems with the time-delay and the random disturbance is studied.Considering the influence of the state quantizer and the control quantizer on systems,a feedback control strategy with double quantizers is designed,which is different from the design method of the single quantizer.By connecting the state quantizer and the control quantizer with two dynamic scalars,a one-step control method is proposed to ensure the exponential synchronization of drive-response systems.2)The feedback control problem of time-varying delay systems with quantization of the measurement signal and the control signal is discussed.In particular,by using a system enhancement method,the time-varying delay systems can be represented as descriptor systems,which is useful for designing a quantized feedback controller.Based on the Lyapunov stability theory,combined with the Wirtinger inequality and the S-procedure,the corresponding H_?performance index can be reached.3)The asymptotic stability problem of nonlinear systems with unmatched quantization parameters is investigated.By designing observer-based control strategy,an adaptive sliding mode feedback control method is proposed to effectively eliminate the influence of unmatched quantization parameters and drive the state trajectory of systems to the sliding mode surface.4)The quantization control problem of actual DC motor systems is studied.By designing the adjustment scheme of quantization parameters to make the DC motor systems asymptotically stable,the corresponding H_?noise attenuation level can also be achieved.