The Stability Analysis Of Networked Control Systems And Sampled-data Control Systems

Early 40s of 20 century, the control systems had been used in the field of industry.The control system is constructed by relay and local-mounted controller. Now, thecontrol systems have developed at a fast speed with the aid of computer. Intelligentcontrol systems give birth to in the times. The third generation of control systems isconsisted by computer and microprocessor. In the recent decades, the networkedcontrol systems (NCSs) whose nucleus is net has being developing at speed. Becausethe computer has been used widely, and if we have no computer, we wouldn’t live andwork. The NCS is investigated from network designing and control designing. Thepurpose of network designing is to design more effectually network protocols,topological structure and scheduling strategy; the tasks of control designing aremathematical modeling, controller designing, et al.First, summairze the situation of NCSs and sampled-data system, and showimportant theoretical and practical significance.Second, some lemmas and theoretical knowledge used in the paper are given.Third, the stability problems of networked control systems with network-induceddelay and data packet dropout is considered. A new bounding approach is proposed toobtain a less conservative stability criteiron. Finally, a numerical example is given toshow the effectiveness and the benefits of the proposed stability criteira.Forth, Based on a Lyapunov-Krasovskii functional, the problem on thedelay-dependent feedback control design for discrete-time networked controlsystems with interval time-varying delay is discussed. The design scheme of thedelay-dependent feedback control which satisfied the requirement of design is alsoachieved. Then the controller parameter K can be obtained by using a conecomplementary lineairzation algorithm to solve the obtained nonlinear matrixinequality.Fitfh, we study the stability analysis problem for sampled-data control systems withcontrol inputs missing. The ifrst method, for the simplicity of technical development,only two different sampling peirods are considered whose occurrence probabilities aregiven constants and satisyf Bernoulli distirbution, which can be further extended tothe case with multiple stochastic sampling peirods. By applying an input-delay approach, the probabilistic sampling system is transformed into a continuoustime-delay system with stochastic parameters in the system matrices. By linear matirxinequality (LMI) approach, sufficient conditions are obtained, which guarantee thestability of the system with control inputs missing. Moreover, an controller designprocedure is then proposed. An illustrative example is included to demonstrate theeffectiveness of the proposed techniques. The second method, a suiffcient conditionfor exponential stability is developed for a class of switching signals with averagedwell time. The sampling peirod is not required to be a constant, and the onlyassumption is that the sampling intervals are less than a given upper bound. By usingthe input delay approach, the vairable sampled-data control system with control inputsmissing is transformed into switched systems with varying-time delay consisting oftwo subsystems. A class of switching signals with average dwell time approach isidentified to guarantee the stability. The state decay estimate is explicitly given. Anexample of control system is given to show the effectiveness of the proposed result.