Robust Control Of Networked Control Systems With Time Delay

Networked Control System (abbreviated to NCS), namely, it is the result of development of computer technology, communication technology and control technology. It indicates that control system tends to be networked, integrated and distributed, and it has unparalleled superiority compared with traditional control system. With network in it, there are some new questions on NCS research.Robust Control which began in 1950s has always been hot spots of international controlled studies. There are many uncertainty system structures or parameters in most of systems. The results of using precise mathematical model to analysis the system, or the controller of designing, do not meet engineering requirements. In recent years, people started to uncertain systems robust control problems, and made a series of research results.In this paper, considering NCS induced delay, a NCS platform is designed and built based on PROFIBUS bus. For network induced delay, the PROFIBUS bus protocol is analyzed, PROFIBUS Data Link Layer and Token circulation are analyzed, too. The time delay problem of the PROFIBUS network is studied, and bus cycle time calculation formula is given.Then, the composition of network induced delay is summed up. In the assumption that the controller node and actuator node is time to work under the premise driven mode, the mathematical model of the closed-loop system is established. According to the mathematical model, the H∞state feedback controller of NCS with network induced delay is designed. Considering an example, the state feedback controller of NCS is gotten by using LMI.Considering the specific NCS platform, using the controller designed, and using the Matlab, the theoretical simulation of the NCS with network induced delay is done. The results show that the method proposed is effective, and the effect is good.