激光跟踪系统中轴承内圈跳动引起的测量误差分析

Measurement error caused by inner race runout of bearing in laser tracker

分析了激光跟踪系统中两回转轴的轴承内圈跳动引起的测量误差,建立了误差的数学模型。根据该模型绘制了测量误差在测量空间的分布图。指出由轴承跳动引起的测量误差不可忽略。当轴承跳动量一定时,最大测量误差位于俯仰角等于π/2的平面上。根据该误差模型,跟踪系统的设计者可以预先估计不同精度等级的轴承跳动引起的误差大小,以选择适合系统设计精度的轴承等级。同时,该模型还指出使用跟踪系统进行测量时,应尽量避免将被测点设置在系统俯仰角等于π/2的平面上,以获得高精度的测量结果。

After analyzing the measurement error caused by the inner race runout of two rotary axes bearing in laser tracking system （LTS）, the mathematical model of errors was established. According the mathematical model, the error distribution diagram in the measurement column was obtained. It is pointed out that the errer caused by bearing runout can not be ignored and the biggest er- ror is on the plane whose pitching angle equals π/2. Based on this error model, the designer of the tracing system can pre-estimate the size of the errors caused by different accuracy grade bearing runnout so as to select bearing grade that is suitable for system design accuracy. At the same time, the model also indicates that, when using tracing system to carry out measurement, the point to be measured should not be set in a plane whose pitching is equal to π/2 so as to obtain a measured result with high accuracy.