Analysis And Control Of Networked Control Systems With Time Delays

With the rapid development of computer communication network technology, thenetworked control systems have become a development tendency of the control systems, andnow this kind of systems have been a hot research scholars in worldwide. Compared with thetraditional point-to-point control systems, the networked control systems have advantages ofless wire, information sharing and easier system installation and maintenance, high flexibility,etc. It has been widely applied in automotive, aerospace, industrial manufacturing fields, etc.However, the intervention of the communication network brings about the problems ofnetwork-induced delay and packet dropout during the process of data transmission, whichleads to a decline in performance or even instability of control systems. Thus, analysis andstudy of NCSs becomes more complex.The stability analysis and controller design problem of networked control systems withtime delays is investigated. Based on the Lyapunov stability theory and the linear matrixinequality method, this paper is concerned with the state feedback control, observer-basedfeedback control and dynamic output feedback control for NCS. The main research works ofthis paper are as follows:First of all, a networked control system with state delay and input delay simultaneouslyis considered. In the case that not all state variables are measurable, the stability andperformance analysis of the closed-loop system are discussed by using the linear matrixinequality method and then the observer-based H-infinity controller is designed.Secondly, a state feedback H-infinity controller of the NCS with network delays anddata dropouts is designed in this section. The system can be modeled as a system withtime-varying delays and a sufficient condition for asymptotic stability and specificperformance indicator by using the Lyapunov-Krasovskii functional is derived. For easysolution, transforming these conditions into LMIs with equation constraints by introducingnew variables, then the state feedback H-infinity controller can be constructed by solvingthese LMIs.Finally, the problem of dynamic output feedback control for NCS with delays is studied.Discussing the two kinds of network delays respectively, and the system can be modeled as ahybrid system with both continuous and discrete items. Then the dynamic output feedbackcontroller is designed easily in terms of solving LMIs.Furthermore, each section gives numerical examples and the results of simulationsdemonstrate the effectiveness of the proposed approaches.