Controller Design And Stability Analysis Of Networked Control Systems

With the popularization of the computer networks technology, the growth of power of network functions and increasingly perfect of network performance, control systems have broader application prospects. The plants are more and more complicated; control systems are developing toward decentralization and intelligence. Complex control systems are usually divided into several distributed individual subsystems and they are flexible, simply designed and easy to install and maintain. With the maturity of the network technology, users are able to proceed long distance data communication and inter-operation. The cost, complexity and maintenance are significantly reduced. Because of the advantages of network technology, extensive research and application have been concentrated on put data networks into the practice of long distance industrial control. Adding communication network into feedback control loop increases the complexity of analysis and design of control systems. So one of the major concerns of networked control systems (NCSs) is to guarantee the real time property and stability of control systems. NCSs have become one of the most popular research interests in current international control field. The research on NCSs has important theoretical meanings and also has extensive application prospects.This thesis systematically introduces the definition, development and characteristics of NCSs, summarizes current control methods for NCSs. The effects of network-induced time delays and network data packet dropout etc, are analyzed. Controller design methods are proposed to solve the stability problem that these characteristics bring to NCSs.For the network-induced time delays, on the basis of the research of the published papers, we employ a new Lyapunov functional and the free-weight-matrix method to gain less conservative results. Also, the controller design and stability analysis for the NCSs with the time delay in the plants arealso presented. The correlation between network-induced delay and the time delay in the plant has been preliminarily studied. We also consider interval type network control delay in terms of the real networks, design the controller and give the system stability conditions. For each situation, we give numerical examples to prove the validity of design methods. For the data packet loss, we present a brief explanation and management.