【作者】 张健；

【导师】 李杏华； 刘保义；

【作者基本信息】 天津大学 ， 电子信息， 2023， 硕士

【摘要】 在化石能源日益枯竭和低碳行动逐渐普及的背景下,国家开始大力推进新能源汽车的发展。声音警报系统(Acoustic Vehicle Alerting System,AVAS)可以在车辆低速行驶时发出声响,达到提醒行人的目的,进而有效降低安全隐患。作为新能源汽车中的一个电控单元,AVAS应支持诊断功能,通过统一诊断服务(Unified Diagnostic Services,UDS)实现。目前国内外有关诊断软件的实现方案较为成熟,但价格昂贵、操作繁琐,且对AVAS的故障诊断不具备很好的针对性,难以满足诊断功能快速开发与测试的要求。因此本文基于UDS诊断服务,设计一套AVAS的诊断系统,主要完成的工作如下:1)设计了基于UDS的AVAS诊断系统的实现方案,明确各模块之间的作用与关联。介绍了CAN通信架构、网络层相关知识与报文传输流程,为后续诊断系统的实现提供基础。2)完成了系统诊断功能的设计。设计了诊断服务统一结构,并实现映射调用机制,方便诊断服务的调用并提高代码生成的效率。设计故障诊断功能,包括故障检测的控制、数据管理以及检测流程,并完成了四种故障诊断模型的建立,实现了故障模型的成熟与恢复机制。设计安全访问功能,为种子增加熵源,提高了种子生成的随机性。设计错误处理机制,增强安全访问功能的可靠性。3)编写了AVAS诊断系统上位机软件。采用基于模板引擎的方法,通过对配置项进行实体类设计,利用可视化操作获取项目元数据,实现了对诊断功能相关代码的自动配置功能。将代码配置与诊断测试功能相结合,在诊断代码自动生成的同时,生成部分诊断服务与报文指令,提高诊断测试案例的配置效率。为测试功能加入自定义报文指令与脚本编写功能,进一步提高诊断测试的灵活性。4)搭建了诊断系统测试平台,进行了配置功能验证实验和诊断测试功能验证实验,证明了上位机软件功能的可用性。利用上位机软件的配置和诊断测试功能,对故障诊断和安全访问功能进行参数配置和诊断测试实验。实验结果表明,故障诊断和安全访问功能均满足设计指标,本文所设计的诊断系统对于快速开发不同诊断需求的AVAS项目具有较好的实用价值。更多还原

【Abstract】 In the background of the depletion of fossil energy and the gradual popularization of low-carbon actions,the country has begun to vigorously promote the development of new energy vehicles.The Acoustic Vehicle Alerting System(AVAS)can sound when the vehicle is driving at a low speed to alert pedestrians and thus effectively reduce safety hazards.As an electronic control unit in the new energy vehicle,AVAS should support diagnostic function,which is realized through Unified Diagnostic Services(UDS).At present,the implementation schemes of relevant diagnostic software at home and abroad are relatively mature,but the cost is expensive,the operation is complicated,and the fault diagnosis of AVAS is not well targeted,which is difficult to meet the requirements of rapid development and testing of diagnostic functions.Therefore,this dissertation designs a diagnostic system for AVAS based on the UDS diagnostic service.The main work completed is as follows:1)The realization scheme of AVAS diagnosis system based on UDS is designed,and the functions and associations between each module are clarified.The CAN com-munication architecture,network layer related knowledge and message transmission process are introduced to provide the basis for the realization of the follow-up diagnosis system.2)The design of the system’s diagnostic functions is completed.A unified structure for diagnostic services is designed,and a mapping call mechanism is implemented to facilitate the call of diagnostic services and improve code generation efficiency.Fault diagnosis functions are designed,including fault detection control,data management,and detection process.The establishment of four fault diagnosis models is completed,realizing the maturity and recovery mechanism of fault models.A security access func-tion is designed to increase the randomness of seed generation by adding entropy sources to seeds.An error handling mechanism is designed to enhance the reliability of the se-curity access function.3)The upper computer software of AVAS diagnostic system is written.Using a template engine-based method,entity class design is carried out on configuration items,and project metadata is obtained through visual operations to achieve automatic config-uration of related diagnostic function codes.Combining code configuration with diag-nostic test functions,partial diagnostic services and message instructions are generated while the diagnostic code is automatically generated,improving the configuration effi-ciency of diagnostic test cases.Custom message instructions and script writing functions are added to the test function to further improve the flexibility of diagnostic testing.4)The test platform of the diagnostic system is built,and configuration function verification experiments and diagnostic test function verification experiments are con-ducted,proving the availability of the upper computer software functions.Using the configuration and diagnostic test functions of the upper computer software,parameter configuration and diagnostic test experiments for fault diagnosis and security access functions are carried out.The experimental results show that the fault diagnosis and se-curity access functions meet the design indicators,and the diagnostic system designed in this article has good practical value for quickly developing different diagnostic needs for AVAS projects.更多还原