考虑飞秒激光跟踪仪仪器轴系的几何误差会影响仪器的指向精度并最终影响坐标测量精度, 本文研究了激光光轴与竖轴的几何误差对仪器测量精度的影响。提出了激光光轴与竖轴的同轴度标定方法, 以降低其不重合带来的跟踪测量误差。首先, 基于几何光学原理建立了光轴与竖轴的几何误差模型, 分别分析了光轴与竖轴的倾斜与平移误差对仪器测角精度的影响。 然后, 针对设计的仪器提出了基于旋转成像原理的光轴与竖轴同轴度的检测方法, 并设计了一套同轴度检测装置。最后, 基于该检测装置, 通过调节两组双光楔完成了激光光轴与竖轴的倾斜与平移误差的标定。结果显示, 经标定校准后激光光轴与竖轴的角度误差为3.4″; 平移误差为26.1 μm, 得到的结果为仪器后续建立误差补偿模型奠定了基础。

As the geometric errors of shafts in a femtosecond laser tracker directly lead to pointing error and limits the coordinate measuring accuracy of the instrument, this paper researches the effects of geometric errors between optical axis and vertical rotary shaft in the laser tracker on measuring accuracy of the instrument. It proposes a calibration method for the coaxiality of optical axis and vertical rotary shaft to reduce the tracking measuring errors from the misalignment between optical axis and vertical rotary shaft. Firstly, a mathematical model of geometric errors between optical axis and vertical rotary shaft was built based on geometrical optical principles, and influences of the tilt and translation between optical axis and vertical rotary shaft on measuring angle errors were analyzed. Then, a coaxiality detecting method based on the rotation imaging principle and image processing algorithm was proposed, and a set of coaxiality detecting device was designed. On the basis of the detecting device, the tilt and translation between optical axis and vertical rotary shaft were calibrated by adjustment of dual wedges. Results show that the angle error of optical axis and vertical rotary shaft is 3.4″ and the translation error is 26.1 μm after calibration, which meets the design indicator of femtosecond laser tracker. This work establishes a theoretical foundation for the subsequent system errors.