【作者】 赵世强；

【导师】 陈伟；

【作者基本信息】 吉林大学 ， 车辆工程， 2011， 硕士

【摘要】 电动助力转向(EPS)系统的出现改善了汽车低速行驶时的转向轻便性及高速行驶时的稳定性,EPS能够与其他电子控制系统相结合,提高汽车的驾驶安全性和舒适性。EPS具有节能环保、占用空间小、路感良好、安装维修方便等优点,它的使用范围已经从最初的微型车向中高级轿车、跑车、越野车以及商用车和客车发展,因此,EPS有着广阔的发展前景,是当前汽车技术发展的热点之一。本文首先对汽车转向系统的发展历程进行了简单的介绍,分析了EPS国内外的发展现状;然后对EPS进行了详细的介绍,包括:EPS的分类;EPS的优缺点;EPS的典型结构工作原理及关键部件;接着比较了EPS三种助力特性曲线,为后面建立实时仿真模型提供了理论基础,然后介绍了EPS性能评价方法;对EPS的控制策略进行了介绍。通过第一章和第二章的介绍对EPS系统有了较为全面的认识,为循环球EPS试验台的搭建奠定了一定的理论基础。第三章首先说明了搭建试验台的必要性,然后对EPS试验台方案进行了对比分析,最终通过比较电液伺服系统和电液比例系统,并根据试验台的要求,选定电液比例加载系统为本试验台的阻力加载方案;然后介绍了循环球EPS试验台的工作原理并对试验台总体布置进行了规划与设计;最后介绍了循环球EPS试验台的主要技术指标及试验台所应实现的基本功能与试验台的用途。第四章中对试验台硬件系统进行了设计选型,本章的重点是对阻力加载系统部件的设计选择,在选型确认的过程中对某些部件的结构、特点、工作原理等进行了介绍,并给出了所确定型号的基本参数;然后介绍了试验台数据采集系统,数据采集系统主要由数据采集卡和工控机组成。第五章首先对xPC Target进行了介绍,介绍了在xPC Target基础上构建实时仿真系统的方法,并说明了试验台xPC Target信号采集步骤;然后,建立了八自由度车辆模型和轮胎模型,轮胎模型采用Unitire1.0稳态模型,整车模型和轮胎模型完全可以满足试验台实时性的需要,另外还建立了轮胎垂直载荷模型和前轮侧偏角模型;在转向系统模型部分,分别建立了循环球转向器模型、电机模型、控制器模型,其中,电机电流采用PID控制,助力特性采用直线型助力特性曲线;基于Visual C++ 6.0设计了试验台人机交互界面,对试验台主机和目标机之间采用的串口通信方式进行了介绍,然后,介绍了人机交互界面各个模块的组成及功用。更多还原

【Abstract】 The EPS improves the steering portability when the vehicle speed is low and the controllability and stability when the vehicle is in high speed, the EPS and other electronic control systems can be combined to improve vehicle safety and driving comfort. The EPS has several advantages, such as, energy conversion and environmental protection, small space, good steering feel, and convenient installation and maintenance, its range of application has grown from the original mini-cars to high-class cars, sports cars, SUV and commercial vehicles and passenger cars. Therefore, the EPS has broad prospect, and is one of the hot spots of automotive technology currently.Firstly, this paper introduces the development of steering system simply, summaries the status of the EPS domestic and foreign. Then introduces the EPS in detail, including: EPS classification, EPS advantages and disadvantages, operation principle of a typical EPS structure and key components. And then compares the curvers of assist characteristic of all the three kinds, which provides the theoretical basis for the establishment of the real-time simulation model, then presents the evaluation methods of the EPS performance, introduces the control strategy of the EPS. The introduction of the EPS system by chapter one and two lays the foundation for the establishment of the test bench for recirculating ball-type EPS.In the third chapter, this paper firstly explains the necessity of building test bench, then compares the test bench plan, and ultimately by comparing the electro-hydraulic servo system and electro-hydraulic proportional system, and in accordance with the requirements of the test bench, selects the electro-hydraulic proportional system as the resistance loading plan. Then presents the operation principle of the test bench for recirculating ball-type EPS and plans and designs the overall layout of the test bench. Finally, presents the main technical indicators of the test bench and the basic functions which should be realized and the useage of the bench.The fourth chapter designs and selects the components of the hardware system, the emphasis of this chaper is the design of the components of resistance loading system, in the selection of the components, introduces the structure, characteristics and operation principle of certain parts, and gives the fundamental parameters of the determined components. Then introducs the data acquisition system of the test bench, which is consisted of data acquisition card and industrial computer.Chapter five were introduces the xPC Target, and presents the method of the building real-time simulation system based on the xPC Target, and describes the the signal acquisition step of the xPC Target. Then establishes the eight degrees of vehicle model and Unitire1.0 steady-state model, which can fully meet the needs of real-time, and in addition establishes the tire vertical load model and the front wheel side slip angle model. In the steering system model, establishes recirculating ball-type steering model, motor model which current uses PID control, and controller model which uses straight-line type assist characteristic. The man-machine interface is designed based on Visual C++ 6.0, and the serial communication which connects the host PC and target PC is introduced, and then introduces the components and function of each module of the man-machine interface.更多还原