Study Of Networked Control System With Asynchronous Characteristics

A real-time control system whose feedback loop is closed via a common serialnetwork is called Networked Control System (NCS).Or,NCSs are one type of distributedcontrol system when sensors,actuators,and controllers are interconnected bycommunication networks.Since informations in NCSs are transmitted throughcommunication network,and bandwidth is limited,some basic issues such asnetwork-induced delays,packet dropout,multi-network transit,multiple-packettransmission exist.Time-variant transit period,network scheduling,single- packet transitand disorder are also problems to be analysed and considered in NCSs.This dissertation mainly studies NCSs with asynchronous characteristic.Besides,statefeedback method and predict compensate method are used to design NCSs with long-timedelay.Three kinds of models of NCSs with network-induced delays,packet dropout,single/multiple -packet transmission are established first.These NCSs are modeled asasynchronous dynamical systems with rate-constraint.Stability of these NCSs is thenanalysed.Estimators are designed to guarantee stability of these three NCS models.Estimatordesign and stability of NCSs with single-channel and dual-channel network are firstdiscussed respectively under single-packet transmission situation.As to NCSs withmultiple-packet transmission,the emphasis is on estimator design and stability of this kindof NCSs with single- channel transmission.The integrity design of these NCSs is analyzed using asynchronous dynamica theory.Fault-tolerant controllers of these three NCS models are design separately.Integrityproblems are studyed when network informations are transmitted in single/multiplepackets under the situation of sensors/actuators failures.Parametric expressions ofcontrollers are given based on feasible solution of linear matrix inequality (LMI).We call network control systems as NCSs with long delays when network-induceddelays are lager than one sample period.Situations of this kind of NCSs are morecomplicated and more difficult to deal with.Methods of solving NCSs with long delays are then more important accordingly.Such NCSs are studied in this dissertation.Twokinds of control methods are used to deal with stability of these NCSs.State feedbackmethod and adaptive predicted method are used respectively.In addition,a multi-modeladaptive contol approach is proposed in order to solve the problem of delays showinglarge span,diversification and different distributions.In each section,examples and simulation results are also given as research result toshow the efficiency and correctness of these methods presented before.Work of the the whole discourse is summarized and future prospect of NCSs isdisscussed at the end of this dissertation.