The Research Of Optimized Control Methods For Network Control System

Network-based control system has become more and more popular in control system since the development of communication and network technology. When compared with the other traditional control systems that without network, the network control system have the following advantages: (1) less wiring; (2) installation with low cost; (3) diagnosis and maintenance easily, etc. However, the limitation of network bandwidth results several new issues in the NCS which the conventional control systems haven't encountered. These new issues include network-induced delay, packet dropout and clock aynchronism. In this dissertation, networked control systems with delay and packet dropout are discussed. The main research works are as follows:(1) The characters and composition of networked induced delay have been discussed firstly. An experimental model is studied and established to simulate the networked control systems. The negative effects of network-induced delay and packet loss on control performance are simulated and analyzed.(2) Data-based control theory is introduced to analyze and control the networked control systems instead of model-based theory. The advantage of data-based control is that the system can be well controlled just with online data. It provides as way to avoid the effect of modeling error. Since networked-induced delay exists commonly in NCS, here the NCS with short delay is studied. The approach to obtain Markov parameters of the system and steps to solve optimal control law are proposed. The numerical experiment shows that the control performance can be well satisfied though our method. Furthermore, considering the dynamics of the network, an adaptive data-based control method for NCS is discussed which can compensate the shortages of off-line controller design. The effectiveness is also proved by numerical experiment.(3) The networked control systems with long delay and packet dropout are discussed. As the above methods can not be used directly in such systems since the data we obtained is not sufficient, a data-based predictive control approach is presented. We give the method of controller design and application steps. Simulation experiment shows that data-based predictive controller is effective for the NCS with time delay or packet loss...