基于模糊推理的奥迪A6轿车发动机故障诊断系统方案设计书.docVIP

基于模糊推理的奥迪A6轿车发动机故障诊断系统设计 摘要：汽车是一个复杂的机械系统，发动机作为汽车的动力源，在汽车中起着重要的作用。特别是在电子控制技术的广泛应用，使汽车进入整车的电子化阶段。同时，也毫无疑问的带来了故障检测诊断的复杂化。要快速的诊断出汽车的故障，需要极其丰富的维修经验和专业的维修知识，并要同先进的诊断设备相配合。因此，本文在收集整理汽车专家的维修知识和经验的基础上，开发针对奥迪A6轿车电控发动机故障诊断系统。本文首先论述了汽车故障诊断技术及其特点、方法，并从宏观上论述了汽车故障诊断专家系统的发展过程。接着在研究奥迪A6发动机电控燃油喷射系统和专家系统的基础上，确定了采用符合专家常规思维的正反向混合的模糊推理策略作为诊断的推理方法，实现了故障快速准确的诊断。在模糊诊断矩阵中隶属度的确定是整个诊断推理的关键，它的准确性决定了推理的准确性。本文采用常用的二元对比排序法确定故障的隶属度，并进行可信度的计算。利用计算机技术将专家的经验和知识以计算机语言的形式表示出来，通过友好的人机交互界面实现故障的诊断、知识的查询等功能，来引导用户逐步进行深入诊断，最终确定发动机故障的部位，并提出维修建议，并不断修改完善知识库，从而达到维修专家的水平。 关键字：电控汽油发动机；汽车故障检测诊断技术；故障检测诊断系统；模糊推理；隶属函数 Based on the fuzzy inference Audi A6 sedan electronic control engine fault diagnosis system design Hou Fei (School of Transportation , Communications and Transportation, Jiaotongxve0602 Grade2006, 062925234) Abstract: The automobile is a complex machinery system. The engine that is automobiles power supply plays an important role in the automobile. Especially with the widespread application of the electronic control technology, it makes the automobiles enter the new electronic age. At the same time, these is no double that it makes the repair work complicated. In order to diagnose vehicle faults quickly, that need for extremely rich experience and professional knowledge of diagnostician with advanced diagnostic equipments. Therefore, on the basis of experts’ knowledge and experiences, fault diagnosis system of Audi A6 sedan was developed in this paper. To begin with, this paper talks about the fault diagnosis system characters and methods of the automobile. Then it discusses the development of the expert system. Moreover, based on the study of the electronic fuel injection and the expert system, I determine to use the diagnostic module’s inference method which is in line with the pros and cons fuzzy and mixed inference of professional conventional thinking. And the system achieves rapid and accurate diagnosis. The membership of fuzzy diagnosis matrix is the key in the whole reasoning. The paper uses dual