The Control Strategy Research Of Networked Control System

Due to the rapid development of computer and communication technologies, the control system become more and more distribution. The networked control system (NCS) has became one of the hot research. The definition of NCS is that the closed-loop feedback control system connected by real-time network. The components of control system exchange information through real-time network in NCS. Network control is the objective requirements of the remote control. The intelligence of sensors, actuators and other field devices provides the necessary conditions for application of communication networks the development of various Field Bus and Industrial Ethernet technologies resolve the problems of reliability and opening in NCS. All mentioned above lead to the application of NCS becoming reality. Network leads a lot of convenience also brings many problems, such as:network time delays, packet loss, network scheduling and allocate bandwidth and so on. These problems make great difficulties to the design and research on the NCS. In this paper, based on the analysis of NCS s characteristics,base problem and the research status of home and abroad, the issue of network time delays is the major research direction of my paper.For the issue of network time delays, this thesis made the work of two aspects as following:1. Delay analysis. First, analyzed the composition of time delay, the impact of Delay on the system and the impact of driven on the time delay. Finally, the simulation intuitive expressed random time-delays and fixed time delay to the influence of system model.2. The time delay compensation. Based on the previous research on the NCS, for the issue of compensation for network delay, this paper presents two kinds of method as following:(1). In network control system, uncertain time-delay caused the uncertainty of system model, so the uncertain object establish a model of fuzzy, applying fuzzy self-tuning control method compensate the delay in network control system. This method reduces the impact of delay on the system, and achieves good result.(2). Time-delay compensation of a class of random and long time-delay Networked Control System was investigated. Because of the impossibility of measuring directly the system state, a kind of state observer with the ability to compensate random long time-delay is designed, thus enabled to improve the performance of the system.