Several kinds of evaluation methods for the uncertainty in coordinate measurement are introduced and it points out that most of these methods are failed to the uncertainty evaluation for special objectives because of lack of theory support or practicability. Therefore, this paper investigates the uncertainty evaluation of gear measurement with Coordinate Measurement Machines (CMMs) by the Monte Carlo method. Firstly, a measuring model is established based on the files for the calibration and compensation of the specific CMM, then the mode is used to obtain measuring results with a large number of sample points. Using these simulated results, the uncertainties can be evaluated more conveniently. Finally,the Monte Carlo method is successfully used in evaluating measurement uncertainty of gear profiles and obtained stable results show that the maximal difference among the results is less than 0. 03μm when the typical uncertainty is 0. 96μm. The paper suggests that Monte Carlo method can support specific uncertainty measurement and can change the situation that common evaluation method can not be suitable for the commercial CMMs.%介绍了坐标测量中几种常用的不确定度评价方法.指出传统的三坐标测量机的测量不确定度评价方法大都不适用于评价坐标测量中面向对象的测量不确定度,并对使用蒙特卡洛方法评价测量不确定度进行了研究.首先,根据三坐标测量机详细标定文件及补偿策略说明建立测量模型.然后,将测量中的采样点通过测量模型生成大量测量结果,并以此评价测量不确定度.在齿廓评价实验中,评定齿廓误差的测量不确定度为0.96 μm时,多次评价结果之间的最大差值不超过0.03 μm,具有可靠的理论依据和较稳定的评定结果.文章指出,目前商用三坐标测量机大都不能为特定的测量对象提供测量不确定度报告,使用蒙特卡洛方法有希望改变此现状.
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