CMM面向形位测量任务的不确定度评定

发布时间：2018-10-18 18:37

【摘要】：测量的目的是为了准确获取被测量的量值,由于测量过程中未知系统误差与随机误差的影响,导致测量结果存在测量不确定度。测量不确定度表征的是被测量量值的分散性,是测量结果应包含的重要参数。三坐标测量机(CMM)是机械测量领域重要的精密测量仪器,理论上可实现任何尺寸及几何误差便捷快速的测量。在形位误差测量方面,虽然多数CMM的测量精度不及圆度仪、自准直仪等专用仪器或量具,但其具备测量功能多样性和便捷性等优点,因此更为广泛地应用于现代工业制造领域。论文选择CMM作为研究对象,重点研究了其形位测量任务下的测量不确定度评定问题。着重解决CMM形位测量任务的测量不确定度评定建模,以及各不确定度分量的量化等问题。给出了一套完整的、具有普适性的CMM形位测量的不确定度评定流程。主要研究工作包括:首先,基于黑箱模型思想,提出了量值特性指标法的CMM形位测量不确定度评定模型,并对CMM测量不确定度来源进行了分析;其次,根据CMM形位测量的特点及相关的理论依据,提出以最大允许探测误差MPEP、最大允许示值误差MPEE来分别量化形状、位置测量任务的示值误差所引入的不确定度分量;再次,对用蒙特卡洛法评定测量不确定度进行了深入系统地研究,给出蒙特卡洛法与自适应蒙特卡洛法两种不确定度分量的合成方法,并与传统的GUM方法进行了对比,分析了GUM法的局限性;最后,选择CMM平面度、平行度测量任务为实验对象进行了实验研究。实验结果表明:所述方法可有效解决CMM面向形位测量任务的测量不确定度评定问题。由于示值误差引入的不确定度分量在合成时占据优势,且不服从正态分布,因此采用蒙特卡洛法进行不确定度合成更为科学、合理。
[Abstract]:The purpose of measurement is to obtain the measured value accurately. Because of the influence of unknown system error and random error in the process of measurement, the measurement result has uncertainty. The uncertainty of measurement represents the dispersion of the measured values and is an important parameter to be included in the measurement results. Coordinate measuring machine (CMM) is an important precision measuring instrument in the field of mechanical measurement. In theory, it can be used to measure any size and geometric error conveniently and quickly. In the aspect of shape and position error measurement, although the measurement accuracy of most CMM is less than that of roundness instrument, autocollimator and other special instruments or measuring tools, it has the advantages of diversity and convenience of measuring function, so it is more widely used in the field of modern industrial manufacturing. In this paper, CMM is chosen as the research object, and the evaluation of measurement uncertainty under the task of shape and position measurement is emphatically studied. This paper focuses on solving the measurement uncertainty evaluation modeling of CMM shape and position measurement task and the quantization of each uncertainty component. A complete and universal evaluation procedure of uncertainty of CMM shape and position measurement is presented. The main research work includes: firstly, based on the thought of black-box model, the evaluation model of uncertainty of CMM shape and position measurement based on quantitative characteristic index method is proposed, and the source of uncertainty of CMM measurement is analyzed. According to the characteristics of CMM shape and position measurement and relevant theoretical basis, this paper proposes quantifying the uncertainty components of shape and position measurement task by using maximum allowable detection error (MPEP,), maximum allowable indication error (MPEE), respectively. In this paper, the evaluation of measurement uncertainty by Monte Carlo method is studied in detail. Two methods of combining the uncertainty components of Monte Carlo method and adaptive Monte Carlo method are given, and compared with the traditional GUM method. The limitation of GUM method is analyzed. Finally, CMM flatness and parallelism are selected as experimental objects. The experimental results show that the proposed method can effectively solve the measurement uncertainty evaluation problem of CMM for shape and position measurement task. Because the uncertainty component introduced by the indication error occupies the advantage in the synthesis and does not accept the normal distribution, it is more scientific and reasonable to use the Monte Carlo method to synthesize the uncertainty.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG83

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