平行双关节坐标测量机圆光栅测角误差补偿技术

Compensation of Angle Measurement Error of Circular Gratings for Parallel Dual-joint Coordinate Measuring Machine

该文探讨了一种三自由度(DOF)平行双关节坐标测量机的测量原理和测量模型。分析了该测量机上的圆光栅测角误差对测量机测量精度的影响,给出了测角误差的补偿公式,利用该公式优化了测量机的测量模型。采用标准多面棱体和光电自准直仪对2个圆光栅的测角误差进行实验检定,并对测角误差修正前后的平行双关节坐标测量机测量精度进行了实验比对。结果表明,测量的极限偏差由0.033 mm降至0.015 mm,而标准差由0.0141 mm降为0.0061 mm,说明修正2个圆光栅的测角误差可大幅提高该测量机的测量精度。

This paper investigates the measurement principle and model of a parallel dual-joint coordinate measuring machine （PD-CMM） which has three degrees of freedom （DOF）. The influence of the angle measurement errors of the circular gratings on the measurement precision of PD-CMM is analyzed. The error compensation equations are analyzed, and based on the equations, the measurement model of the PD-CMM is optimized. Using a multifaceted prism and an autocoltimator, the angle measurement errors of the two circular gratings are inspected. The measurement precisions of the PDCMM after and before the error compensation of the angle measurement errors of the circular gratings are compared. The results show that the limit deviation decreases from 0.033 mm to 0.015 mm, and the standard deviation decreases from 0. 0141 mm to 0. 0061 mm. The precision of the PD-CMM can be extremely improved by correcting the angle measurement errors of the two circular gratings.