Open Network Control System Of Research And Application

The open network control system is an integrated applications.At the control level,it belongs to the research area of networked control system.At the control architecture level,it is a distributed control system. And the control strategy needs to synthesis the network's performance and the controller design.In this dissertation, the key problems of network control system,such as protocol ,time delay ,and the forecast and evaluation of time delay,and control strategy are studied .The evolution of network control system is firstly introduced and analyzed systematically,open NCS is brought forward as the main topic of this dissertation.Considering that network control system is the product of the combination of information technology and traditional control system , it naturally make communication protocol become key factor of NCS.Then in second chapter some current protocols widely used in NCS are compared . However ,many improved protocol or special protocol appeared to meet demand of NCS, but in comparison with general protocol ,it takes flaws like peculiar limits and closed request which contradict to open developing trend of NCS, and makes no contribution to popularize NCS in wide range. It is more effectual for building NCS to make the best use of general protocol. In the end XML-RPC is used to realize a new remote control method and relevant application is taken into practice.The third chapter lay stress on time delays in NCS, including its generation mechanism, modeling, evaluation, and control strategy.After these analysis,an online delay-valuation approach is introduced with a different view from the familiar method in next chapter, which characterize the time delay utilizing network traffic predicted by wavelets.Although Internet is a very complex and gigantic system to analyze diagnostically,its characteristics and behaviors can be reflected from network traffic.Research on traffic can enhance our understanding of the work mechanism of network and improve the accuracy of time delay estimation.Finally, control strategy of nonlinear time-variant network control system...