Research On Scheduling Algorithm Of Networked Control System

Network Control System (NCS) is a network of distributed control system based on thecontrol loop, is the use of serial communication network that connects intelligent field devicesand automation systems, closed loop so as to form a feedback control system. In networkcontrol system, to achieve information transmission between the nodes through thecommunication network, has to share information resources, greatly reducing the number oflinks, efficient, reliable, flexible, easy to extend and maintain. At present, through thecommunication network of public or private to replace the traditional control system of pointto point structure has become increasingly popular.This paper expounds the network control system research background and significance,the basic problems, network scheduling research; this paper introduces three kinds of controlnetwork and the simulation tool Truetime; introduced the basic knowledge of networkscheduling involves; introduced the dynamic, static scheduling strategy, including the staticscheduling algorithm RM, DM dynamic scheduling algorithm, as well as EDF, LLF, analysis,summarizes the advantages and disadvantages of each kind, scheduling strategy, andintroduces the realization of scheduling algorithm simulation using Truetime toolbox; basedon several typical scheduling algorithms, key has conducted the research to the MixedScheduling Algorithm in networked control systems.By using Matlab/Simulink simulation tool based on Truetime-1.5, this paper constructs asimulation platform of networked control systems, the co simulation of control andscheduling, in a separate and joint effects of several factors on packet loss rate, delay,disturbance, construct a variety of different network environment, respectively, the simulationstudy on the static and dynamic scheduling algorithm RM scheduling algorithm for EDF in atypical NCS, scheduling of the two typical algorithms of DC motor compared.This paper uses the CAN bus as the research object, through to the dynamic, staticscheduling algorithm and the hierarchical scheduling mechanism of the mixed schedulingalgorithm (MTS) analysis and research, put forward a kind of improved hybrid schedulingalgorithm IMTS, IMTS algorithm of the messages in the network is divided into hardreal-time news, soft real-time messages and non periodic non real time message, andrespectively on these three kinds of message priority assignments, including hard real-timemessages of highest priority, soft real-time news time high, non periodic non real timemessage minimum. For hard real-time message scheduling, using LLF or EDF algorithm forscheduling, and combined with the first come first service ideas; for soft real-time messagesand non periodic non real time news, mainly uses the DM scheduling algorithm, which combines the RM algorithm and the first come first served policy. Finally, using theMatlab/Simulink TrueTime-1.5toolbox to simulate the IMTS algorithm based on theimproved algorithm, which has good scheduling performance.