Modeling And Design Of Networked Control Systems Based On Active Disturbance Rejection Control

In the networked control system,the communication network is used as the main medium of information transmission.The sensor,controller and actuator are connected to a common bus.It greatly facilitates the expansion and maintenance of the system.Moreover,it is of high system flexibility and high utilization of resources.However,the introduction of the network has changed the mode of information transmission in the control system.Problems such as sampling period jitter,network induced delay and so on have brought new problems and difficulties to the design of the control system.Therefore,based on the concept of active disturbance rejection control(ADRC),modeling and design of networked control systems with jitter of sampling period and network induced delays are investigated respectively in this thesis: mismatched uncertainties,network-induced delay and short time-varing delay.The main work is summarized as follows:1.The sampling jitter problem is investigated.The dynamics induced by the sampling jitter is described as an additative disturbance,then an extended state observer and a corresponding state feedback stabilizing controller is designed for discrete time networked control systems,and the lumped disturbance is estimated and rejected.2.The network-induced delay compensation problem is investigated.The dynamics induced by the network-induced delay is described as an additative disturbance,and the networked control systems with delays is modeled as a contrinuous time linear system with additative disturbance.Then,a delay-induced disturbance observer and a corresponding state feedback stabilizing controller is designed,and the delay-induced disturbance is estimated and rejected.3.The modeling and control problem is investigated for networked control systems with time-varying short delays.The networked control system with short time-varing delays is modeled as a class of discrete-time system with bounded additative disturbance.Then,an active disturbance rejection controller with extended state observer is designed,and the networked control system is stabilized by the designed disturbance rejection controllers.