前轮定位对汽车低速转向回正性能的分析

Analysis of the Effect of the Front Wheel Alignment on Steering Returnability of Motor Vehicle at Low Speed

为研究汽车的低速回正性能,根据相对运动的原理,研究了车轮转角与车身抬高量的关系。首先用一种新的方法推导了该关系,推导时假设主销轴线不动,选择车轮中心在最高位置时作为计算的零位置,并且把车身的抬高量计算分为两部分:一部分为车轮中心相对于主销轴线的高度变化,另一部分为车轮外倾角变化导致的车轮中心离地面高度变化。然后,把推导的结果和相关文献进行了对比和分析,结果发现车轮外倾角的变化也会对车身抬高量产生一定的影响,而假设车轮接地点不动的推导结果则会造成较大的系统误差,误差大小取决于车轮定位参数。

In order to study the steering returnability of motor vehicle at low speed,based on theory of relative motion,the relationship between the body height change and the steer angle of the steer wheel is studied.A new method is used to deduce the relationship,and the kingpin axle is assumed fixed in the deduction,and the highest position of wheel center is chosen as zero position.The height change involves two factors： one is the height of the wheel center relating to the kingpin axle,and the other is the height of the wheel center relating to the ground regarding the wheel camber change.Then,comparisons are conducted among relating papers.Results show that camber change can influence the height change at a certain extent,and deduction with the assumption of fixed tire contact center will cause system error,and such error is determined by wheel alignment parameters.