Research On Networked Control System With Access Constraints And Delays

With the rapid development of control technology,computer network technology and communication technology,the research of networked control systems has received widespread attention in recent years.Compared with traditional control systems,networked control systems have some advantages as reduce system wiring and costs,easy to expand and maintain,reduce costs,etc.,which make networked control systems successfully applied to many fields,such as automatic driving systems,transportation systems,remote monitoring and data acquisition systems.In the networked control system,the controller exchanges data with system components such as sensors and actuators through a communication network.Due to network communication bandwidth limitations,only limited-number sensors and actuators can obtain network resources to communicate with remote controllers per sampling period,which is called medium access constraint.In the process of signal transmission,network induced delay is inevitably brought about.Due to the existence of medium access constraint and delays,system performance is degraded or even unstable.Firstly,it introduces the purpose and significance of the topic selection,discusses some basic problems of networked control topics,reviews the research status of networked control systems,and analyzes the existing problems and deficiencies.Then,for the networked control system with network induced delay and communication limitation,a new design method of networked control system is proposed by utilizing lifting technology,optimal control and switching system theory.The main contents are as follows:For a class of linear time-invariant networked control systems with communication constraints,the lifting control technology is used to construct a networked control model integrating control and scheduling.According to Kalman filter technology,the optimal state estimation is carried out,and then by using the optimal control theory method,the optimal controller that meets the quadratic performance index is designed to stabilize the system.Finally,the effectiveness of the proposed strategy is verified by Matlab simulation.A networked control system with random delay and random event-driven communication is investigated for the design problem of the optimal controller.Firstly,the continuous networked control system with random delay is discretized;then the system is modeled as a Markov linear jumping system according to the stochastic communication mechanism between the controller and the actuator/sensor;secondly,the optimal controller satisfying the quadratic performance index is designed by using the linear quadratic optimal control rate to realize the stabilizing control of the networked system.Finally,the correctness and effectiveness of the proposed method are verified by simulation.Finally,a summary has been done for all thesis,and the research works in further study are presented.