Research On Real Time Scheduling Algorithm Of Mine Communication Based On Network Control System

The real-time nature of the communication determines the safety level of the mine monitoring system,and the high real-time performance can detect the occurrence of the accident and avoid the effect in time,the state also has invested enormous human and financial resources in coal mine safety.With the development of science and technology,the monitoring system is constantly upgrading,the hardware transmission rate has been able to reach Gigabit level over the past 20 years,but in many cases,it could not improve the real-time performance of the system to the greatest extent.In order to solve the above problems,the improved network scheduling algorithm is proposed to reduce the transmission delay and improve the real-time communication.Network induced delay is an important part of network delay in networked control systems,and the network delay reduces the real-time performance of the system,so this paper studies two different queue scheduling algorithms to ensure the flow of information in real time and throughput.1)the mixed scheduling algorithm,the algorithm combined with priority,queue length and the average waiting time of the information frame to determine the order of the output queue,the way of queues divided into priority is described in detail in the paper,namely through information period,deadline of information and the information frame arrival time dynamically allocating priority.The experimental results show that the proposed algorithm can adjust the bandwidth of each queue by setting the parameters,and improve the real-time performance of the information frame and reduce the packet loss rate.2)non-additivemeasures queue scheduling algorithm,the algorithm can use the way of non-additivemeasures to realize scheduling control.In this paper,the method of obtaining the preference relation or the evaluation value of the subset of the criteria is introduced in detail,which is based on the combination of the analytic hierarchy process,the maximum entropy principle and the 2 order additive measure.In the network control system based on bus Ethernet,the CSMA/CD protocol has the characteristics of instability,high collision rate,low channel utilization and low throughput.Logistic mapping CSMA/CD protocol is established in this paper.The Ethernet bus time response model and study a new CSMA/CD protocol-improved dynamic parameters,and the protocol uses the Logistic mapping function showed dynamic changes in the parameters of Mu under different trend which can dynamically adjust the dynamic parameters of P to increasethe channel utilization rate.The algorithm using different scheduling methods under different loading conditions: At high load conditions,it uses the way of polling in the form of node scheduling;at low load conditions,it uses dynamic parameters of P Logistic mapping CSMA/CD protocol to realize the node scheduling.