汽车主销后倾测量模型误差分析及标定方法

Error analysis of measurement model and calibration method for automobile caster

针对四轮定位仪采用线性模型测量主销后倾的误差问题,建立了精确的测量模型。根据该模型得出影响主销后倾测量精度的因素为主销内倾、车轮外倾及转角盘转角。分析了由主销内倾产生的测量误差,得出当主销内倾大于10°时线性模型不能进行准确测量的结论。为解决无法检定校准四轮定位仪测量主销倾角结果的现状,提出了在汽车纵横两平面内主销倾角独立生成的检定原则,研发了四轮定位仪检定装置。试验表明:受检四轮定位仪当主销两倾角均大于15°时,其测量误差大于10′,存在零点和线性度系统误差,且系统误差随主销倾角的增大而增大,从而解决了测量主销倾角量值检定的问题。

To improve the measuring precision of the automobile caster by a linear model on the four-wheel aligner, a precise measuring model was built. The model showed that the factors affecting the caster measuring precision are the kingpin inclination, the camber, and the turntable angle, the measuring error caused by the kingpin inclination was analyzed and it was concluded that it is impossible to measure the caster precisely with the linear model when the kingpin inclination is more than 10°. To calibrate the measuring results of the kingpin obliquity on the four-wheel aligner, a calibration apparatus was developed based on the principle of independent acquisition of the kingpin obliquities in the vertical and horizontal planes of the automobile. The experiment results show that the measuring errors are more than 10′ and these are zero point error and the non-lincar system error when the two obliquity angles of the kingpin are more than 15°, and the system errors increase as the kingpin obliquities increase. The automolile caster measuring results calibration problem has thus been solved.