Analysis And Design Of Networked Control System Based On Cognitive Control

With the rapid development and integration of Control Science,Computer Science and Communication Science,Networked Control System(NCS)has become a research hotspot for scholars in the field of control.NCS is a distributed control system,and it has the advantage of remote control that traditional control systems cannot match.In addition,NCS can be maintained and debugged conveniently,and it is an important component of infrastructure for the operation of modern society.However,the introduction of communication network also brings some problems to the control system,such as packet loss,delay,and the safety of control system caused by network security.The main contents of this dissertation are as follows.(1)When dealing with network delay and packet loss problems,idealized assumptions about the character of delay and packet loss are first made in the existing literature,and then a corresponding control algorithm based on these assumptions is designed.However,these assumptions hardly meet the reality of Wireless Networked Control System(WNCS),because the character of delay and packet loss of WNCS is complex.Based on the idea of Cognitive Control,this dissertation does not makes idealized assumptions about the character of delay and packet loss of wireless network environment,but a Cognitive Controller is added to the control system: the Cognitive Controller learns a strategy in Perception-Action Cycle,and the retry limit of Media Access Control(MAC)layer of wireless network and the length of command sequence of the Physical Controller are adjusted by Cognitive Action of the Cognitive Controller.In this dissertation,an omnidirectional wheel mobile robot is selected as the plant.The performance of WNCS with Cognitive Controller and WNCS with fixed configuration are compared,and the task of the WNCS is to control the omnidirectional wheel mobile robot to track the sinusoidal reference trajectory.Simulation results show that WNCS designed in this dissertation can deal with network delay and packet loss better.(2)As for jamming attack problem of wireless network,Cognitive Risk Control(CRC)systems are designed based on the idea of Cognitive Risk Control.A motorcade consist of three vehicles is selected as the study object.The designed CRC systems are mounted on the first vehicle and the second vehicle of the motorcade.As the motorcade goes ahead,Task Switch Control module output switch signal based on output signal of Perceptor and the prediction signal of Bayesian Classifier.If there is no attack speculated by the Task Switch Control module,the Cognitive Controller is connected to the system to adjust the transmission power of wireless signal;otherwise,the module that running Upper Confidence Bound(UCB)algorithm is connected to the system to adjust communication channel between vehicles.Simulation results of motorcade using fixed channel,random channel and equipped with CRC system are compared.Simulation results show that motorcade equipped with CRC system can mitigate the interference of Jamming Attack on the distance and speed difference between vehicles better.In this dissertation,Matlab-based True Time toolbox is used to simulate and verify the designed WNCS and CRC systems.Finally,the work of this dissertation is summarized,and the future work is prospected.