激光跟踪仪多边测量的不确定度评定

激光跟踪仪多边测量是大型高端装备制造现场溯源的重要手段,正确评定其不确定度是确保制造过程量值统一、结果可靠的关键。本文提出了一种准确、快速的激光跟踪仪多边测量的不确定度评定方法。从仪器误差、环境干扰及靶球制造误差等方面分析激光跟踪仪多边测量的不确定度来源。针对多边测量的输出量为多维向量的特点,重点研究基于多维不确定度传播律(GUM法)的不确定度合成方法,同步评定目标点坐标和跟踪仪站位的不确定度。最后,介绍了点到点长度的不确定度计算方法。实验表明:GUM法评定的不确定度结果与蒙特卡洛法(MCM法)的结果相比,坐标不确定度偏差小于0.000 2 mm,相关系数偏差小于0.01,满足数值容差,且GUM法用时仅为MCM法的0.08%;点到点长度测试的En值均小于1。因此,基于GUM法评定激光跟踪仪多边测量的不确定度具有可行性及高效性,且评定结果正确、可靠。

Evaluation of uncertainty in multilateration with laser tracker

Multilateration with laser tracker is an important method for on-site traceability in large-scale equipment manufacturing processes. An accurate evaluation of uncertainty is the key to ensuring quantitative accuracy in manufacturing processes. In this paper, we reported an accurate and fast technique for the evaluation of uncertainty in multilateration with laser tracker. First, the sources of uncertainty in multilateration were analyzed; these primarily include instrument errors, environmental conditions, and manufacturing errors of the target. Next, based on the propagation of uncertainty for multivariate measurement error models (GUM), the uncertainty in multilateration with laser tracker was estimated. Finally, the uncertainty in the point-to-point length was calculated. Our experiments reveal that the differences between the uncertainty values evaluated using GUM and Monte Carlo method (MCM) are within the numerical tolerance limit. The deviation in the uncertainty in coordinates is less than 0.000 2 mm, whereas that in the correlation value is less than 0.01. The time required for the GUM method is only 0.08% of the time required for the MCM method, and the value of En obtained from the point-to-point length test is less than 1. Thus, this study reveals that the evaluation of uncertainty in multilateration with laser tracker based on the GUM method is feasible and efficient, and the obtained results are accurate and reliable.