机床导轨滚转角测量误差分析

Error Analysis on the Roll Angle Measurement of Machine Tool's Guideway

为研究激光外差干涉法滚转角测量中反射器入射角误差对测量灵敏度的影响,利用琼斯矩阵,建立了一种新的测量光路数学模型。新模型在原有模型的基础上考虑了高反镜入射角误差的影响,基于多层介质膜作用机理,量化了高反镜入射角误差引起的反射光变化,进而推导出高反镜入射角误差对滚转角测量灵敏度的影响。结果表明:测量系统的放大倍数随高反镜入射角不同而变化,并在入射角为36°时取得理论最大值720倍,达到高反镜正常角度入射时放大倍数的6倍;实验验证当高反镜入射角为38°时,系统放大倍数达到346倍,若采用分辨率为0.01°的相位计,滚转角的测量分辨率可达0.1″。实验结果验证了理论分析的正确性,并且提供了一种通过改变高反镜入射角来提高滚转角测量灵敏度的思路。

To evaluate the influence of incident angle error of the reflector on the roll angle measurement of machine tool＇s guideway, a new mathematical model was established by Jones matrix method. The new model takes the influence of the incident angle error of high-reflectivity mirror into consideration based on the existing model. The reflected light of the mirror with different incident angles was analyzed based on the action mechanism of multiple dielectric films. Then the influence of incident angle error of reflector on the roll angle measurement was calculated. Results showed that the measurement gain coefficient varied with the incident angle and a maximum value of 720 was obtained when the incident angle was 36-deg, a 6-fold increase compared with previous results. In the experimental setup, we measured a gain coefficient of 346 at the 38-deg incident angle to the mirror. A roll angle measuring resolution 0. 1-arcsec was attained using a phase meter with a resolution of 0.01-deg. The theoretical analysis of the new model was verified, which also provides a measuring sensitivity enhancement approach by carefully controlling the incident angle of the mirror.