Design And Applications Of Networked Control Systems

A considerable research attention has recently been focused on a class of networked control systems (NCSs) which are typically spatially distributed systems wherein the communication between sensors, actuators, and controllers occurs through a shared resources-limited communication network. The insertion of communication network into traditional point-point control system makes the analysis and design of control applications complex.The modeling, optimization, analysis and control of networked control systems by multiple utilization of computing, communication and control technologies are studied in this dissertation. The main contents of this dissertation are outlined as follows:Firstly, a combinatorial model of controlling and communication parameters fornetworked control systems is presented based on analysis of the industrial network characteristics. In order to optimize an unavoidable tradeoff between the control performance and network parameters, an optimization algorithm is established.Secondly, an online evaluation technique for network-induced delay by redesigning the application protocol without any additional apparatus is proposed. A computational method for network-induced time delay online evaluation and a lower bound on the transmission period by using automatic route trace technique are presented respectively. A simple decision-making for the data packet dropout is also discussed.Thirdly, due to the variation of control performance for the networked Quality-of-Service (QoS) deterioration, a controller design method for NCSs is presented. A network-parameters-dependent sufficient condition for the existence of guaranteed cost controller for NCS is also given.Fourthly, the performance of a networked control system can be improved if thenetwork can guarantee QoS. Due to time-varying network traffic demands and disturbances, QoS requirements provided by a network may change. In this case, an approach for networked three-layer water tank control system using a predictive compensation strategy to adapt the detrimental effect of networked QoS induced by communication networks is proposed. A compensation strategy is also designed for both the given networked QoS and system performance targets.Fifthly, According to the remote control system characteristics: multi-requirements; multitask and high request for real-time performance. A feature-oriented mapping approach is proposed and a remote control system based on C/S and B/S multi software architecture is developed. Under the proposed system some experimental results are also presented.Finally, the conclusions are given and the direction of future research is presented.