Modeling And Analysis Of Networked Control System With Proportional-integral Output Feedback

With the development of network technology, more and more networks (e.g. the Internet) have been applied to the distributed control system, which is termed networked control system (NCS). This architecture promotes ease of maintenance, greater flexibility and low cost. Although the networks make it convenient to control the large distributed system, there are many control issues that occur in the conventional control systems, such as network time-delay, data packet dropout, multi-packet transmission and so on.In this paper, by studying the Chinese and English journals and papers, we do research on the H∞guaranteed cost control of NCS and controller design of multi-packet NCS under Proportional-Integral (PI) output feedback controller.Firstly, the background, composition and features of NCS are introduced. The background of the Proportional-Integral-Derived (PID) control and guaranteed cost control are also discussed.Secondly, the problem of H∞guaranteed cost control of NCS with PI output feedback controller is studied. Aimed at NCS with networks existing both between sensor and controller and between controller and actuator and a quadratic cost function, it can obtain the condition of the existence of the H∞guaranteed cost control by using Lyapunov stability theory and Linear Matrix Inequality (LMI), which can not only make a closed loop system stable, but also assure that its cost is not over a certain determinable upper bound. Furthermore, the designing method of the H∞guaranteed cost controller is also presented. Finally, an example is given to illustrate the feasibility of the problem.Thirdly, the controller design of multi-packet NCS with PI output feedback controller is studied. A modeling method for such NCS with short time-delay is presented. This NCS is modeled as linear switched control system under certain switching sequences. With the switched control system theory and robust stability theory, the sufficient conditions of the asymptotic stability of NCS with multi-packet transmission are obtained. A numerical example demonstrates the conclusions are feasible and effective.Fourthly, NCS under PID output feedback controller with short time-delay and long time-delay are modeled, respectively.At last, the main work of this thesis and the future development of NCS are discussed.