载货汽车车载运行状态监控网络设计与信息调度传输方法研究

The existing dynamic monitoring technology of truck are mainly focus on positioning and dispatching,but monitoring and analysis on the technical condition of vehicle working unit was lacked. In this project, trucks equipped OBD will be selected as the research object, and the research method is consist of theoretical analysis, computer simulation and vehicle condition test, and the CAN-based monitoring network of truck operating condition will be built firstly, with the OBD system, which could extracted operation and fault information provided by units, for example, engine controlling unit. By analyzing the domestic and foreign operation informatron dispatching algorithms of vehicle data bus, the dynamic dispatching algorithm which is suitable for the vehicle monitoring networks will be researched, and real-time information will be dispatched and collected according to its security priority. the impact of data compression algorithm on the reduction of transmission flow will be analyzed, so the information varying slowly will be compressed, a mixed configuration package protocols of multi-state monitoring parameters will be developed to transmit the processed data to the remote monitoring center station through wireless network. This project firstly used the simulation network technology to optimized the performance of dispatching and compression algorithms, and then set up the system bench and prototype of vehicle to operate the multi-driving condition on-board test and performance evaluation, and finally put forward a scientific and typical technologies of the operation information dispatching and remote compression transmission. Research results will offer a theory and technology foundation for the remote dynamic monitoring system of truck performance, and the level of vehicle safety operation will be raised too.

目前货车动态监控以定位和调度为主，缺乏对车辆工作单元技术状况的综合监控分析。课题以配置OBD系统货车为研究对象，采用理论分析、计算机仿真和实车工况试验相结合的方法，首先构建基于CAN总线的货车车载运行状态监控网络，结合OBD系统主要对发动机控制单元提供的运行状态信息进行提取；通过对国内外汽车总线调度算法的分析研究，研究适用于车载监控网络的车辆运行信息动态调度算法，根据安全优先级对实时信息进行调度分配采集；研究数据压缩算法对缓变信息进行冗余压缩处理以减少其无线传输量，制定监控参数混合组态打包协议并通过无线网络将处理后的数据传输给远程监控中心站。课题研究首先利用仿真网络对调度和压缩算法进行性能优化，最后组建系统台架及样车原型进行多行驶工况实车检测和性能评估。最终形成一套科学的、覆盖主流车型的运行信息调度与远程压缩传输共性技术。为研究货车远程性能监控系统奠定理论和技术基础，提高车辆安全运营水平。

课题以配置CAN网络系统的车辆为研究对象，采用理论分析、计算机仿真和工况试验相结合的研究手段，形成了一套车辆运行状态信息调度与远程压缩传输技术方法。.首先，为降本增效地实现营运车辆远程监控与故障诊断，提升车辆运行安全监管水平并降低事故隐患，项目提出并设计营运车辆运行状态远程监控系统。可通过车载CAN总线实时对车辆工作单元的关键参数如制动压力、油压、转速以及故障码信息等进行采集，并通过GPRS模块传输给远程监控中心系统分析应用；为提升监控信息采集和传输效率，提出车辆CAN信息分类采集与混合组态传输方法；研究基于游程的字符串相对编码数据压缩算法，对采集的海量监控数据进行压缩后传输，通过试验验证，数据平均压缩比达到32.17%。能够有效降低数据无线传输成本。经实车试验证明，整体系统工作稳定可靠，能够实现预期设计功能。.其次，项目针对电动汽车TTCAN网络在传输随机信息方面的实时通信需求，提出了基于信息周期相关组装载（PCGL）的数据压缩算法。通过对同步相的带宽率进行压缩，加速了事件触发消息的实时响应。项目同时对PCGL调度方法进行了详细描述。通过SAE电动汽车消息标准的调度和测试结果表明，该方法在保证实时触发的信息效率的前提下，能够使事件触发消息的实时效率显著提高。.最后，针对CAN总线中存在的低优先级信息会因为高优先级信息频繁占用总线而出现的死锁问题，在车辆控制系统中引入柔性时间触发机制组建柔性事件触发控制器局域网（FTT-CAN），针对周期信息和随机信息，分别在FTT-CAN的同步相和异步相中采用最早截止期优先（EDF）调度和动态提升优先级（DPP）调度，介绍了FTT-CAN触发原理，提出了基于EDF和DPP的动态调度算法，将该调度算法应用于典型电动汽车控制系统模型的调度，验证了该调度算法的优越性。