Research On Time-Delay Compensation And Scheduling Methods For Networked Control Systems

Along with the extension of the control system scale and fast development of network technologies, control systems based on control networks are widely applied in the modern industry control, which have advantages of less wires, high reliability, good flexibility and share of information resources, etc. However, since the communication network has been inserted in the networked control system, some new issues such as network-induced time delay, network scheduling, multiple-packet transmission and dropping network packets appear. Therefore, analysis and design of NCS has been a hot research problem in the control theory and control engineering area.The key issues of time delay and scheduling in the networked control system (NCS) are studied in this dissertation. Main achievements are as follows:(1) The detail summary of some basic contents, issues, and recent research on networked control system is made.(2) To the existing network-induced time delay, different methods for time-delay compensation in NCS are introduced based on modeling of NCS. As for uncertain time delay, some combined compensation schemes including Fuzzy-PI controller and Fuzzy-PI controller based on Smith prediction are presented firstly; then Stabilization is analyzed in detail, stability region of the networked PI control system with fuzzy logic modulator is provided. These control methods are validated through the simulation of network-based controlled DC motor.(3) For the improvement of communication of the whole control network as well as the improvement of every loop's performance and the network resources utilization, NCS scheduling is studied from the point of view of the network, two methods are introduced: The application of real time scheduling to NCS; Network bandwidth allocation scheme based on scheduling of sampling periods and sampling...