The Scheduling Of Networked Control System

With the extension of the control system scale and the rapid development of the computer network and communication technology, the network and communication technology are applied to the control field and lead to the new development of Networked Control System (NCS), which are distributed, networked and intelligent. The research of NCS becomes one of hot focus by the domestic and oversea scientist. For the intervention of network in the control system, the networked delay is unavoidable. Furthermore, the limited network bandwidth and load capability shared by the many control loops lead to decrease the performance of control system and instability. The performance of NCS is related to not only control strategy but also the scheduling of network resource. In this thesis, it is mainly studied the scheduling of networked control system based on the identification of online networked delay in order to optimize performance of the whole system.Firstly, the development and some features specific to NCSs are introduced. Some basic problems and recent advances in research area are discussed in detail.Secondly, focus on the networked-delay of NCS, the delay (sensor to controller) and the delay (controller to actuator) are discussed separately. Based on the established NCS model, the networked delay influence on the performance of feedback control loop is analyzed in detailed example. Furthermore, Using filter operation, it is presented an identification method which can estimate the networked-delay online, as well as the availability of this method and the stability of NCS.Thirdly, the scheduling of networked control system based on the on-line networked delay identification is studied. The scheduling algorithm for network control systems can adjust the sampling period and allocate the bandwidth of the network for three types of data, guaranteeing the system performance and increasing network resources. With the simulation by Matlab/True time software, the proposed scheduling method is available and can optimize the whole system performance.Finally, the research conclusions are presented. The innovative ideas and theremaining problems that need further research of the scheduling of networked control systems (NCSs) are pointed out in this thesis.