Uncertainty estimation of shape and roughness measurement
Uncertainty estimation of shape and roughness measurement
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DOI：
10.6100/ir607374
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
M. Morel
中科院分区：
文献类型：
--
作者：
M. Morel
测量表面或形状的最常见技术之一是机械探测。尽管自20世纪30年代初以来一直在使用，但尚未设计出计算特定于任务的不确定性预算的方法。在某些情况下，指南和统计估计是常见的，但没有一个明确的方法来进行所有类型的测量和测量任务。一种新的方法，虚拟测量机，已经成功地在坐标测量机中实现，现在应用于一组特定的触针测量仪器，即：·粗糙度; ·圆度; ·收缩（形状测量）。这些类型的机器中的每一种都使用相同的测量原理;用指定的力将触针压在物体上，在物体上移动，并记录触针尖端的轨迹。测量过程及其干扰可以从理论上和数学上描述。对导致测量不确定性的每个干扰或影响因素进行建模，并使用该模型生成模拟（虚拟）测量。虚拟测量取决于影响因素的大小和范围。影响因素的一些示例包括：针尖几何形状、测量力、探头增益系数、测量轴的垂直度等。每个因素在测量时的灵敏度通过所谓的虚拟测量来计算。用虚拟测量值重新计算被测对象的描述参数，给出归因于影响因素或机器参数的不确定性的量。总的不确定性预算由每个机器参数的不确定性的每个贡献组成。该方法成功地实现了两台机器：SV 624-3D（粗糙度和形状）和theRA 2000（圆度，形状和圆柱度）。它示出了一个在线的不确定性预算可以计算指定每个贡献者。由于不仅需要校准增益因子，而且不确定性计算需要更多的输入变量，例如机器参数的校准数据，因此开发了校准工件来执行这样的任务。这些人工制品可用于在车间进行全面和快速的校准，可直接追溯到适当的一级标准。结合高质量软件中用于粗糙度、圆度和形状的虚拟测量机与校准工件，实现了一个强大的测量工具，可以计算这些类型机器的任务特定不确定度预算，并创建可追溯的测量结果，可以通过认证机构认证。
One of the most common techniques to measure a surface or form is mechanical probing. Although used since the early 30s of the 20th century, a method to calculate a task specific uncertainty budget was not yet devised. Guidelines and statistical estimates are common in certain cases but an unambiguous method for all kinds of measurements and measurement tasks is absent.Anew method, the virtual measurement machine, already successfully implemented in CMMs, is now applied on a specific group of stylus measurement instruments namely for: • roughness; • roundness; • contracers (form measurement). Each of these types of machines use the same measurement principle; a stylus is pressed against the object with a well specified force, moved across the object and the trajectory of the stylus tip is registered. The measurement process and its disturbances can be described theoretically and mathematically. Each disturbance or influencing factor which contributes to the uncertainty of the measurement is modeled and with this model simulated (virtual) measurements are generated. The virtual measurement depends upon the magnitude and range of the influencing factor. Some examples of influencing factors are; tip geometry, measurement force, probe gain factors, squareness of measurement axes, etc... The sensitivity of each factor upon the measurement is calculated with so-called virtual measurements. Recalculation of the describing parameters of the measured object with the virtual measurements gives the amount of uncertainty attributed to the influencing factor or machine parameter. The total uncertainty budget is composed out of each contribution in uncertainty of each machine parameter. The method is successfully implemented on two machines: the SV 624-3D (roughness and shape) and theRA2000 (roundness, form and cylindricity). It is shown that an on-line uncertainty budget can be calculated specifying each contributor. As not only gain factors need to be calibrated, but more input variables, e.g. calibration data of machine parameters, are required by the uncertainty calculation, calibration artefacts are developed to perform such a task. The artefacts can be used to perform a total and fast calibration on the shopfloor directly traceable to the appropriate primary standard. Combining the virtual measurement machine, implemented for roughness, roundness and form in high quality software, with the calibration artefacts, a powerful measurement tool is realised which allows to calculate a task specific uncertainty budget for these types of machines and creates a traceable measurement result which can be accredited by accreditation organizations.