Disturbance Rejection Problem Of Control Systems Based On Equivalent-input-disturbance Method

With the rapid development of industrial technology,the disturbance rejection performance of the system has received extensive attention,and the improvement of the disturbance rejection performance of the system has become an important research issue.The improvement of the disturbance rejection performance of the system mainly lies in the accurate estimation of the external unknown disturbance.The equivalent-input-disturbance(EID)method is suitable for all kinds of disturbance rejection,and does not require the state information of the plant,therefore,the method greatly reduces the difficulty of the disturbance estimation,which can estimate the external disturbances under the premise of less accurate information,and compensate the impact of the external disturbance by the control input,improving the stability of the system.The work of this paper is mainly divided into two parts.On the one hand,the disturbance rejection problem for descriptor networked control system is investigated,the traditional EID method is improved and an adjustable gain is designed to improve the disturbance rejection performance of the system,and the network delay is divided into time-invariant and time-varying.On the other hand,the disturbance rejection problem for the sampled system with input delay is discussed.Based on the EID method the effects of input delay on the system is overcame by the observer-predictor-based output feedback control,and a disturbance predictor is designed to predict the future information of disturbance estimation,reduce the influence of the phase delay caused by input delay,and improve the accuracy of the perturbation estimation.The structure of the paper is as follows:In chapter 1,the physical background and application of descriptor systems,networked control systems,disturbance rejection and observers are briefly introduced,as well as the current research status.In chapter 2,the improved disturbance rejection performance problem for descriptor systems based on the adaptive equivalent-input-disturbance method is investigated.In chapter 3,the disturbance rejection problem for the sampled system with input delay using observer-predictor-based output feedback control is studied.Chapter 4 is the summary and prospect of the paper.