Research On Networked Control System Based On Time Delay And Data Packet Dropouts

Rapid development of network information is bringing inestimable change to the world,the network information is the concentrated reflection of information technology, and becomethe main trend of global economic and social development. Under the network environment,the communication network structure of the control systems has aroused widespread concern.Networked Control Systems is a real network which is formed by the framework. Thepresence of NCS overcome a few disadvantage in the conventional control system, expensivecost, low efficiency, and complex structure, it is adapting to the increasing of socialdevelopment. However, there is the limited network bandwidth and unordered datatransmission, which makes the NCS faced many problems. The analysis and design of NCSbecome complicated, due to network-induced delay, data packet dropouts, the driving mode ofnetwork nodes and network scheduling.Based on Lyapunov-Krasovskii stability theory and time-delay systems method, theproblem on stability criterion and state feedback controller design and example simulation forNCS with network-induce delay and data packet dropouts is studied.1. The stability analysis of continuous-time NCS and the design method of stabilizingcontroller are researched. A class of NCS with both network delay and data packet dropout ismodeled as time-varying delay system. By constructing a piecewise Lyapunov-Krasovskiifunctional separate time-varying delay interval effectively, then a finite sum inequality ispresented to deal with delay interval. A less conservation stability criteria is derived. On thisbasis the design method of state feedback stabilizing controller is proposed, throughlinearization of nonlinear term, the MADB guaranteeing the stability of NCS and theparameter of stabilizing controller are obtained. Some simulation results of the Matlabexample show the validity of the proposed method.2. The problem on H∞robust control for discrete NCS is studied. A class of NCS withnetwork delay, data dropout, external disturbance and unknown model parameter is modeledas uncertain time-varying delay system. A sufficient condition subject to the robust asymptoticstability and H∞performance is derived by using Lyapunov-Krasovskii functional, Jenseninequality and reciprocal convex technique. On the basis the parameter of H∞robust controlleris obtained by employing linearization of nonlinear term. A Matlab simulation example showsthe effectiveness and superiority of our result.3. The problem on non-fragile guaranteed cost control for NCS with delay, data dropoutand controller gain perturbation is studied. A sufficient condition subject to non-fragileguaranteed cost controller is established by using free-weighting and convex combination,and the condition guarantees closed-loop system robust asymptotic stability and performanceindex is less than certain upper limit value. The parameter of non-fragile guaranteed costcontroller by employing LMI toolbox. The feasibility of the result is shown by the simulation.