Electronic control unit (ECU) function is based on steering Angle torque and speed of the disk, logical analysis and signal, issue commands to calculate, control the action in addition, boosts motor has a safety protection and self ECU diagnose function ECU through gather current generator voltage engine conditions signal judge its system working condition is normal, once. 3 EPS System Research Situation 3. 1 EPS System Development Situation
EPS system was first by Japanese suzuki motor company in 1988 February development, Cervo small cars in the equipment installed in the Alto, then in 1993, Honda motor company is the world's first put EPS as standard equipment configuration in advanced sports car AcuraNSX, Japan automobile manufacturers then the Mira and mitsubishi's wrath Minica correspondingly installed EPS system since then, electric power to turn Booster motor,The two companies are about 70% models adopted the steering power type EPS starting and GM chose TRW company offers of a transitional technology, including electric hydraulic steering technology,Volkswagen is in its PQ35 was used on the platform of the complex ZF provide double small gear power type EPS.
In a foreign country, EPS system application range is from original mini on commercial to limousines MPV, booster forms from low speed range booster type to full speed range booster type direction.
At present domestic to EPS system research, mainly on the hacking power type with mini car carry EPS system on EPS of university basically has: study of tsinghua university, Beijing university of science and technology, huazhong university of science and technology university in Beijing university of tianjin university of hefei technical university of jiangsu automobile industry of hubei province, wuhan university of technology, college guangzhou Honda flying across SiDi, changhe plough is the earliest equipment models, EPS EPS system makes these cars became the highlight of participates in the market competition. 4 Conclusion
EPS systems involve the sensor technology microelectronics control modern control theory and the traditional mechanical design, EPS to represent the future car power steering technology development direction, will serve as a standard accessories one of the bus, and equipment in power steering field is the dominant so EPS is very wide application prospect, our country is necessary to increase investment on research and development.
附 录B 中文译文
汽车电动助力转向系统发展综述
摘要
综述了国内外汽车电动助力转向(EPS)系统的发展现状,介绍了电动助力转向系统的结构、类型及其特点。分析对比了国内外电动助力转向系统建模及控制策略,展望了电动助力转向系统的发展趋势,指出电动助力转向技术代表未来汽车动力转向技术的发展方向之一,并将在动力转向领域占据主导地位。
关键词:汽车;电动助力转向系统;发展趋势 1 EPS系统的类型与特点 1. 1 EPS系统的分类
早期开发的EPS系统都是低速、驻车转向助力型。目前现有的4种类型的EPS系统都是基于齿轮齿条转向系统的,按照助力电动机的安装位置不同可以分为:转向柱助力型、小齿轮助力型、双小齿轮助力型和齿条助力型。转向柱助力型EPS的助力电动机安装在转向柱上,电动机助力转矩通过蜗杆蜗轮减速增扭后直接加在转向柱上。其优点是电动机可以安装在转向柱的任何位置,成本相对其他几种类型最低;缺点对电动机的转矩波动对驾驶员手感影响较大。小齿轮助力型EPS
的助力电动机通过小齿轮与齿条啮合,电动机的助力转矩直接加在小齿轮轴上。优点是:刚性好,转向路感强。双小齿轮助力型EPS的转向齿条上安装有两个小齿轮,一个小齿轮与转向盘相连,助力电动机通过另外一个小齿轮与齿条啮合,为齿条提供助力。优点是:可以提供相对较大的助力。 1. 2 EPS系统的优点
EPS系统与传统的液压动力转向系统相比有以下优点:
(1)EPS能在各种行驶工况下提供最佳助力。在驻车或停车入库以及低速转向时为驾驶员提供足够的助力,在高速转向时使驾驶员有良好的“路感”,并减小由路面不平所引起的对转向系统的扰动,改善汽车的转向特性。
(2)提高了汽车的燃油经济性,城市工况下燃油经济性可以提高3. 5%,平均节省燃油3%。EPS系统仅在汽车转向时才提供助力,不像传统的液压动力转向系统即使在不转向时,油泵也一直运转。
(3)EPS系统结构紧凑,零件数量较少,便于安装和装配,提高了劳动生产率。由于省去了装于发动机上的皮带轮和油泵,留出的空间可以用于安装其他部件。FIAT公司生产的Punto采用了DELPHI公司开发的电动助力转向系统,装车时间减少了80%左右。
(4)EPS系统取消了液压回路,不存在渗油和漏油问题,减少了对环境的污染,同时又节省了大量的转向助力油。 (5)EPS系统具有自我诊断的功能,便于维修和保养。 (6)EPS系统具有良好的低温工作性能,即使在-40℃的环境
下,EPS系统也能很好地工作,具有更高的可靠性、安全性。 (7)EPS系统最大的优点就是整个系统的性能可以在不改变系统结构的情况下,通过改变系统的控制策略、编程来实现,从而满足不同的车型和不同的驾驶感觉的需要,大大减低了开发的成本,提高了开发效率。
2 EPS系统的关键部件
EPS系统的关键部件主要有转角传感器、转矩传感器、车速传感器、助力电动机、减速机构和电控制单元(ECU)等。 2.1 转角、转矩传感器
转角传感器用于实时检测转向盘的转动方向以及转向盘的位置,转矩传感器用于实时检测转向盘转矩大小,并将信号输送到EPS系统的电控单元(ECU)。转角、转矩传感器的精度问题决定了电动助力转向系统的性能可靠性,加速开发研究性能可靠成本低廉的转角、转矩传感器十分重要,传感器的成本是制约电动助力转向系统市场化的主要因素之一。 2.2 车速传感器
车速传感器用来测量车速的大小。车速传感器一般采用电磁感应式传感器,安装在变速箱上。该传感器根据车速的变化,把主副两个系统的脉冲信号传送给ECU,由于是两个系统,因此信号的可靠性提高了。 2.3 助力电动机
助力电动机是EPS系统的执行元件,助力电动机的特性直接影响到EPS系统控制的难易程度和驾驶员的手感。EPS系统对助力电动机的