电控动力转向系统的故障诊断与检修毕业论文.doc

PAGE PAGE 18 毕业论文 题目：电控动力转向系统的故障诊断与检修 系 部 专 业 名 称 班 级 姓 名 学 号 指 导 教 师 　 年 月 日 电控动力转向系统的故障诊断与排除 摘 要 本文通过对EPS各组成部分和汽车转向系统的分析建立了EPS系统动力学模型，建立了车辆二自由度模型，轮胎模型，并推导出了包括EPS系统、轮胎模型和车辆二自由度模型在内的系统状态空间表达式，然后利用MATLAB/SIMULINK建立了该综合系统的仿真模型。提出了评价装备有EPS系统的汽车的操纵性能指标如转向灵敏、路感，并通过汽车操纵动力学和EPS系统动力学的综合分析，推导了转向灵敏和路感的表达式，然后考察了EPS系统各参数(包括助力机构传动比、电动机转动惯量等）对这两个指标的影响，在此基础上建立了其稳定性准则。最后在满足稳定性准则约束条件和最大化目标函数——转向路感的基础上，建立了电动助力转向系统参数的优化设计模型，进行了系统参数的优化设计，优化后的转向路感好于优化前。在设计EPS系统时，综合考虑EPS系统各可变参数对转向操纵性能的影响可以在获得较好的操纵性能的同时能够降低系统设计的难度。 关键词：转向路感；转向灵敏度；优化设计 Electric power steering system fault diagnosis and maintenance Abstract Through the analysis of components of EPS system and the steering system ‘EPS’ dynamics model, full vehicle model whit two degrees of freedom and tire model was built. Then the state function of the combination system model was deduced and the model for simulation was built via MATLAB/SIMULINK in this paper. Several performance evaluations such as steering sensitivity and steering feel to evaluate the handling performance of the combination system including EPS system and vehicle handling system were put forward and their expressions were deduced after the integral analysis of vehicle’s handling dynamics and EPS’ dynamics. Having investigated the effects of several factors such as gear ratio of the assisting mechanisms and moment of inertia of the motor etc. On these indices, a stability criterion was built. Finally, based on the restrictions of stability criterion and maximize the object function of steering feel, an optimization model of EPS system was built and an example was presented and the steering feel is much better after optimization. In the foundation of general consider the effects of several alterable parameters on steering handling performance, good steering handling performan