Laser beam used as a visualizing measuring axis has emerged as a major candidate technology for 3D shape measurement. Until now, a prime limitation has been the highly-accurate positioning of laser beam in the whole measurement space. A multi-position calibration method for laser beam based on the cyclical error of harmonic turntable is proposed in this paper. A flexible calibration field constructed by CMM and PSD-based laser receiving board is presented. The coordinate of laser spot on PSD is obtained and transformed into CMM coordinate system. The direction vector of laser beam is obtained by linear fitting from a set of calibrated laser spots. Then the laser beams are calibrated in multiple positions. Based on the cyclicity of harmonic turntable, the error model of rotation angle is established by Fourier series function. The rotation angles are compensated in whole-space and the positioning of laser beam is obtained with highly-accurate. The experimental results demonstrate that the RMSE of linear fitting of laser beams is no more than 0.006 mm, the RMSE of the compensated rotation angles is no more than 0.003°, the RMSE of the spatial points is 0.089 mm and the RMSE of the reconstructed distances is 0.060 mm.

用作可视化测量轴的激光束已成为3D形状测量的主要候选技术。到目前为止，主要的限制是激光束在整个测量空间中的精确定位。提出了一种基于谐波转台周期性误差的激光多位置标定方法。提出了由CMM和基于PSD的激光接收板构建的灵活校准场。获得了PSD上激光光斑的坐标，并将其转换为CMM坐标系。激光束的方向向量是通过线性拟合从一组已校准的激光光斑中获得的。然后在多个位置校准激光束。基于谐波转台的周期性，利用傅立叶级数函数建立了转角误差模型。旋转角在整个空间中得到补偿，并且可以高精度地获得激光束的定位。实验结果表明，激光线性拟合的RMSE不大于0.006 mm，补偿旋转角的RMSE不大于0.003°，空间点的RMSE为0.089 mm，重构距离的RMSE是0.060毫米。