Velázquez Jesús, Conte Javier, Majarena Ana Cristina, Santolaria Jorge
Design and Manufacturing Engineering Department, University of Zaragoza, 50018 Zaragoza, Spain.
Instituto de Investigación en Ingeniería de Aragón (I3A), 50018 Zaragoza, Spain.
Sensors (Basel). 2021 Nov 10;21(22):7479. doi: 10.3390/s21227479.
Laser trackers (LT) are widely used to calibrate other machines. Nevertheless, very little is known about calibrating an LT. There are some standards that allow us to evaluate the LT performance. However, they require specialized equipment. A calibration procedure to improve the LT accuracy in an easy and fast way is presented in this paper. This method is based on network measurements where a set of reflectors were measured from different LT positions in a working environment. The methodology proposed deal with the lack of nominal data of the reflector mesh. A measurement scenario was defined, based on error parameter dependence on distances and angles, thus, obtaining those positions more sensitive to errors. The influence of the incidence angle of the laser beam on the reflector was characterized, revealing that its contribution to the LT measurement error can be up to 13 µm. Error kinematic parameters were identified to provide the optimum value of an objective function, where the reflector mesh nominal data were unknown. The calibration procedure was validated with nominal data, by measuring a set of reflectors located on a coordinate measuring machine. The findings of this study suggested that the LT accuracy can be improved up to 25%. Moreover, the method can be carried out by the LT user without requiring specialized equipment.
激光跟踪仪（LT）被广泛用于校准其他机器。然而，关于校准激光跟踪仪的知识却知之甚少。有一些标准可以让我们评估激光跟踪仪的性能。然而，它们需要专门的设备。本文提出了一种以简单快速的方式提高激光跟踪仪精度的校准程序。该方法基于网络测量，即在工作环境中从激光跟踪仪的不同位置测量一组反射器。所提出的方法解决了反射器网格标称数据缺失的问题。基于误差参数对距离和角度的依赖性定义了一个测量场景，从而获得对误差更敏感的那些位置。表征了激光束在反射器上的入射角的影响，发现其对激光跟踪仪测量误差的贡献可达13微米。在反射器网格标称数据未知的情况下，识别误差运动学参数以提供目标函数的最优值。通过测量位于坐标测量机上的一组反射器，用标称数据验证了校准程序。本研究结果表明，激光跟踪仪的精度可提高高达25%。此外，该方法可由激光跟踪仪用户执行，无需专门设备。
