Xi Jianpu, Li Bin, Ren Dongxu, Zhao Zexiang
Appl Opt. 2019 Mar 10;58(8):1907-1916. doi: 10.1364/AO.58.001907.
This paper proposes an offline measurement method for a large aspheric mirror during its grinding stage. A measurement method and mathematical model to realize a three-dimensional (3D) profile measurement for large-diameter aspheric mirrors are proposed, based on a cylindrical coordinate system. The measurement error induced by the alignment error is examined based on the error analysis of the measurement and workpiece coordinate systems. The corresponding pose error obtained through the nonlinear least squares method is eliminated to improve the measurement accuracy. To evaluate the entire surface profile error, a 3D profile model is established. The total uncertainties of the proposed measurement system are also estimated. Comparison experiments for a 300-mm-diameter K9 glass workpiece are conducted on UPFM900 and Taylor Hobson PGI 3D profile instruments, and the profile accuracy is found to be improved from 15.3 to 7.12 μm after eccentricity and tilt error elimination.
本文提出了一种大口径非球面镜研磨阶段的离线测量方法。基于圆柱坐标系，提出了一种实现大口径非球面镜三维（3D）轮廓测量的测量方法和数学模型。基于测量坐标系和工件坐标系的误差分析，研究了对准误差引起的测量误差。通过非线性最小二乘法消除相应的位姿误差，以提高测量精度。为了评估整个表面轮廓误差，建立了3D轮廓模型。还估计了所提出测量系统的总不确定度。在UPFM900和泰勒·霍普森PGI 3D轮廓仪上对直径300mm的K9玻璃工件进行了对比实验，发现消除偏心和倾斜误差后，轮廓精度从15.3μm提高到了7.12μm。
