动态转向系统转向特性研究hyperworks

重庆理工大学硕士学位论文动态转向系统转向特性研究姓名：王伟申请学位级别：硕士专业：车辆工程指导教师：廖林清2011-05-27摘要

- I - 摘 要 汽车转向系统是汽车的一个重要组成部分，主动转向系统是在现有转向技术的基础上发展起来的新型转向系统，它已成为世界汽车技术发展的研究热点和前沿技术，也是汽车现代转向系统发展的重要方向之一。它能同时满足驾驶员对汽车转向系统在低速时的灵活性要求与高速时的稳定性要求。本文以动态转向系统为研究对象，引申出了基于横摆角速度增益来确定动态转向系统理想传动比的途径。 首先对主动转向系统的发展及其工作原理进行了介绍，分析了目前国内外关于主动转向系统的研究现状及其发展趋势，并总结了主动转向系统的特点；分析了动态转向系统的转向原理、机械结构、工作原理及其关键技术，着重研究了动态转向系统的关键部件——谐波行星齿轮机构角度叠加的工作原理；对动态转向系统的主要功能和特点进行了分析总结。 其次，通过对动态转向系统的工作原理与车辆的动力学特性分析，建立了车辆动力学模型、轮胎模型、动态转向系统模型等；在等速圆周转向工况下，得出了驾驶员所期望的横摆角速度和侧向速度；依据动态转向系统的结构分析，建立了动态转向系统的数学模型以及方向盘与转向柱、同步电机子模型。 然后，根据转向系统角传动比的定义引申出了动态转向系统的理想传动比的概念，并给出了在考虑车速和转向轮转角情况下，横摆角速度增益为定值的理想传动比计算公式；以某车型为例，设计了该车型的动态转向系统理想传动比曲面。 最后，对比研究了采用固定传动比与可变传动比转向系统的车辆在可变传动比、转向灵活性及转向稳定性方面的性能，结果表明：在低速时，动态转向系统在减轻驾驶员负担、提高转向系统灵活性、增强稳定性方面都有明显改善；在高速时，动态转向系统降低了转向灵敏度，改善了转向系统灵活性，提高了车辆的安全性。但在车速较高或转向轮转角较大时，动态转向系统对于车辆稳定性的改善有限。 通过对动态转向特性的研究，为动态转向系统的动态响应特性研究奠定了一定的基础，也为进一步的动态转向系统的评价准则的研究提供了依据，同时也对研究车辆运动学分析及其开展台架试验具有一定的帮助作用。

关键词：动态转向系统；理想传动比；横摆角速度增益；转向增益 Abstract

- III - Abstract The steering system is an important part of the vehicle. The active steering system is a brand new kind of steering system based on existing steering technology, and it is becoming one of the hottest projects and advanced technology in the field of vehicle development, as well as an important development direction of modern steering system. The active steering system can meet the demands of steering flexibility when the car running at low speed and steering stability when running at high speed. The dynamic steering system is studied and the way to determine ideal transmission rate of the dynamic steering system, which is based on the yaw-rate gain, is amplified in this paper. Firstly, the development history and the basic principle of active steering system are introduced and research situation and its development tendency in home and abroad are analyzed, also the characteristic of the active steering system is summarized. The steering principle, mechanical structure, working principle and the key technologies of dynamic steering system are analyzed and the angle superposition principle of the key assembly that is harmonic planetary gears is especially studied. The main function and characteristic of dynamic steering system are analyzed as well as be summarized. Secondly, the dynamic model of vehicle, the model of tire and the model of dynamic steering system are established based on the analysis of dynamic performance of vehicle and working principle of dynamic steering system. The yaw-rate and lateral velocity gain which the driver expected are obtained on the working condition that the vehicle steers in the form of uniform circular motion. The mathematical model of the dynamic steering system, the model of steering wheel and steering column and the model synchronous motor are established according to the structural analysis of dynamic steering system. Thirdly, the concept of ideal transmission ratio of dynamic steering system is extended according to the definition of angle ratio of steering system and the computational formula of ideal transmission ratio is given on the condition that the speed of vehicle and turning angle of the steering wheel are taken into consideration as well as the yaw-rate gain is to be seen a fixed value. The curved surface of the ideal transmission ratio of dynamic steering system is designed by a certain car. Lastly, the performance of variable steering ratio, steering flexibility and steering stability are respectively studied and compared when the steering system using fixed 重庆理工大学硕士学位论文 - IV - steering ratio or variable steering ratio. The research results indicate that the dynamic steering system can lighten the driver’s burden, increase the steering flexibility as well as enhance stability obviously when the car running at a lower speed. On the other side, the dynamic steering system can reduce the steering sensitivity, improve the steering flexibility as well as guarantee security of vehicle when the car running at a higher speed. But the dynamic steering system cannot contribute too much for the stability of vehicle when the car running at high speed or the turning angle of the turning wheel is too big. The dynamic steering properties are studied in this paper, which lays foundation for the research of dynamic response characteristic of dynamic steering system and provides guidelines for the research of interpretational criteria of dynamic steering system, as well as helpful for the vehicle kinematical analysis and platform test.