MVB非周期信息调度策略优化

发布时间：2018-12-12 16:26

【摘要】：多功能车辆总线(Multifunction Vehicle Bus,MVB)是列车通信网络系统的重要组成部分。为了更好地理解MVB,本文以列车通信网络为切入点,阐述了列车通信网络的定义、特征、总线和两层拓扑结构,并对包括MVB在内的几种常见的列车通信总线进行分析和比较,简述了MVB遵守的实时协议以及国内外对列车通信网络的研究现状。因为列车通信网络是一种特殊的现场总线,它的发展离不开现场总线技术的进步,所以对现场总线中比较重要的调度理论进行了深入的探讨,对调度算法的分类和典型算法以及算法的可行性分析进行了总结性的概括。在此基础上,本文对MVB的设备、信息类型、介质分配、报文进行了详细的分析。重点研究了MVB非周期信息的调度机制,对调度流程、调度步骤中的关键帧以及信息碰撞时的仲裁过程进行深入的研究。最后介绍了MVB常用的几种动态性能指标。通过对协议中标准调度策略的分析得知,在调度过程中由并发信息造成的仲裁延时会对信息的实时性造成较大的影响,同优先级信息的调度顺序也仅仅是按照信息被搜索到的顺序设定的,没有考虑到不同信息的时间特征要求的不同。针对这些问题,现有的方法优化效果有限,也不能满足实际情况的要求。基于此种状况,本文提出了一种新的调度策略,通过填充帧的使用和信息列表帧的设计,使得调度过程可以避免并发信息的搜索过程。同一从设备上的后来信息如果时限要求较严,本文策略可以大大减小它们的等待延时。这样对于信息的实时性有了较大的改善。同优先级信息按照信息的时限要求进行调度,更加符合实际情况。通过实验验证,本文策略与标准策略、SFS调度策略相比,实验结果在四种性能指标上全面占优。这说明了本文策略在改善信息实时性方面的有效性。通过实验对比,验证本文策略在设备数量增加的情况下的较大优势。
[Abstract]:Multifunctional vehicle bus (Multifunction Vehicle Bus,MVB) is an important part of train communication network system. In order to better understand MVB, the definition, characteristics, bus and two-layer topology of train communication network are expounded, and several common train communication buses, including MVB, are analyzed and compared. This paper briefly introduces the real-time protocol of MVB and the research status of train communication network at home and abroad. Because the train communication network is a special field bus, its development can not be separated from the progress of the field bus technology, so the more important dispatching theory in the field bus is deeply discussed. The classification of scheduling algorithm, the typical algorithm and the feasibility analysis of the algorithm are summarized. On this basis, this paper analyzes the equipment, information type, medium distribution and message of MVB in detail. The scheduling mechanism of MVB aperiodic information is studied emphatically, and the scheduling process, the key frames in the scheduling step and the arbitration process in the event of information collision are deeply studied. At last, several dynamic performance indexes of MVB are introduced. Through the analysis of the standard scheduling policy in the protocol, we know that the arbitration delay caused by concurrent information in the scheduling process will have a great impact on the real-time of the information. The scheduling order of the same priority information is only set according to the order in which the information is searched, and the time characteristic requirements of different information are not taken into account. For these problems, the existing optimization methods have limited effect and can not meet the requirements of the actual situation. Based on this situation, a new scheduling strategy is proposed in this paper, which can avoid the concurrent information searching process by using the fill frame and the design of the information list frame. If the time limit of the later information on the same slave device is strict, the waiting delay can be greatly reduced. In this way, the real-time information has been greatly improved. The same priority information is scheduled according to the time limit of the information, which is more in line with the actual situation. The experimental results show that compared with the standard policy and the SFS scheduling strategy, the experimental results are superior to each other in four kinds of performance indexes. This shows the effectiveness of this strategy in improving the real-time information. Through the comparison of experiments, it is proved that this strategy has a great advantage in the case of increasing the number of equipment.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U270.382

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