利用三坐标测量仪拼接检测大口径非球面面形

为了利用三坐标测量仪实现对大口径非球面面形的检测,提出了大口径非球面面形三坐标拼接测试方法。对该方法的基本原理与具体的实现流程进行了分析和研究,并基于初级像差理论和最小二乘拟合建立了三坐标拼接检验大口径非球面综合优化数学模型。结合实例,对一口径为1 200 mm434 mm的长条形SiC离轴非球面反射镜进行了两个子孔径的三坐标拼接检测,并将拼接测试结果与非球面全口径轮廓检测结果进行了比对,其PV值和RMS值的偏差分别仅为0.073 m和0.042 m;两种方法面形残差的PV值和RMS值分别为0.325 m和0.055 m。

Measurement of large aspheric surface by stitching and coordinate measuring machine

For the purpose to test large aspheric surface by Coordinate Measuring Machine(CMM), the new method combined three coordinate measuring and subaperture stitching testing was proposed. The basic principle and flow chart of the method were analyzed, the synthetical optimization stitching mode and effective stitching algorithm were established based on primary aberration and least-squares fitting. A large off-axial SiC aspheric surface with the aperture of 1 200 mm434 mm was tested by this method with 2 subapertures. For the validation, the whole asphere was also measured by profilometry. The PV and RMS between the two methods is 0.073 m and 0.042 m, respectively; the PV and RMS of residual error is 0.325 m and 0.055 m, respectively.