The Study On The Real-time Method For MVB Network

With the rapid development of network communication technology and bus technology of rail vehicles,The multifunction vehicle bus(MVB) is used to realize the interconnection between the functional equipments of rail vehicles, the application on rail cars in our country is more and more widely.Real-time performance has caused widespread concern in many aspects.And real-time has a crucial impact on the performance of the control system of the vehicles,also, for the protection of safe travel tha is very important.Multifunction vehicle bus is clearly stated in the train communication network standard IEC61375-1 which is developed by the International Electrotechnical Commission.The main function of MVB is to connect the rail vehicles standard equipment to the rail vehicles communication network.MVB is mainly used in railway vehicles, the transmission of data including period data and non-periodic data.If the MVB is used to transfer data, it is necessary to meet the real-time requirements that is presented according to the train communication network.Therefore, this paper focuses on the train control network real-time performance.The analysis for real-time of the article includes three aspects.First of all, the thesis introduces relevant concepts of MVB, the key part is that we summarized the existing real-time transmission algorithms of MVB.According to the MVB bus data types, the paper outlines the real-time algorithms of periodic data and non-periodic data.At the same time,we would take a comparative analysis between algorithms and point out the characteristics of each algorithm.Summed up the real-time algorithm factors of MVB networks which is need to consider in the design process, and the research focus and development trend in the future is pointed out.Also pointed out that the focus of future research and development trends.Then,the characteristics of periodic data would be described in detail in this paper.Aiming to the rules of periodic scanning table data of MVB,we present an optimal design method using differential evolution algorithm in this dissertation.According to the provisions of the international standard IEC61375-1,the paper introduces periodic table generation rules and constraints, and the corresponding mathematical model is established,using the uniform degree as the objective function,the peperiodic scanning table would be established and optimized.Simultaneously,compared with step-by-step fill in the blanks method,differential evolution algorithm has the advantage.Then,the characteristics of non-periodic data would be described in detail in this paper.On the basis of the train communication network protocol and round-robin algorithm,this paper proposed a dynamic priority round-robin algorithm. In the MVB, thedelay among transmission equipments mainly includes waiting to be sent delay and transmitting the packet delay and more. On the basis of dynamic priority, the algorithm can improve the real-time performance of MVB network to transmit the non-periodic data by optimizing the complexity of algorithm, reducing waiting delay and blocking delay. The simulation analysis shows that the algorithm can improve the real-time performance and fairness performance of MVB transmission. At the same time the algorithm also satisfies the requirements of the ICE61375-1.Finally, a summary of the full paper is written.It describes the importance of real-time to the MVB.Moreover,This paper discusses the future research directions of MVB.