汽车主销内倾测量精度分析及校准仪器

Measurement precision analysis of automobile steering axle inclination and calibration apparatus

为解决四轮定位仪测量主销内倾的精度问题,建立了精确的内倾测量模型.分析了主销内倾与传感器测量角间的非线性关系以及主销后倾变化等因素对主销内倾测量精度的影响.讨论了测量误差的分布趋势,当主销倾角大于10°时线性模型测量误差大于10′.针对无法校准主销倾角测量结果的现状,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,研发了精度达到30″的四轮定位仪校准装置.试验表明:四轮定位仪测量主销内倾存在零点误差和线性度系统误差.当受检四轮定位仪主销倾角为15°时,其测量误差为18′,且系统误差随主销倾角增大而增大.试验结果与理论值相符.

Precise metrical model of steering axle inclination （ SAI ） is built for analyzing the four-wheel aligners＇ metrical error. The nonlinear relationship between SAI and sensor＇s measurement angle, and change of caster which affects the measurement precision are analyzed based on the model. It shows that metrical error is more than 10＇ when kingpin obliquity is over 10°. To calibrate metrical result of kingpin obliquity, calibration method of kingpin obliquity is presented according to independent enactment principle in vertical and traverse sections of automobile. A calibration apparatus of four-wheel aligners is invented and its precision is up to 30＂. Experiments show that zero error and linear system error exist when SAI is tested by the four-wheel aligners. Metrical error is 18＇ when the kingpin obliquity is 15°and the system error increases as kingpin obliquity increases. The experimental results correspond to the theoretical analysis well.