基于GUM-MCM的微纳米坐标测量机圆度测量不确定度评定OA

To verify the reliability of micro/nano coordinate measuring machines(CMMs)in roundness measurement and to accurately identify key sources of measurement uncertainty,an evaluation method is established to quantitatively analyze the uncertainty and the influence of various error components on the evaluation results.First,in accordance with the Chinese national standard GB/T 7235-2004,four center calculation methods-least squares,maximum inscribed circle,minimum circumscribed circle,and mini-mum zone-are employed,and the roundness measurement uncertainty is evaluated using the GUM-MCM method.Subsequently,a Random Forest regression model is introduced to establish the relationship be-tween the errors associated with different uncertainty sources(repeatability,temperature variation,cross-talk force,and probe wear)and the resulting roundness error.By employing three evaluation metrics—out-of-bag error increase,feature elimination error increase,and stability weight—the influence of each er-ror source on the roundness error is systematically quantified.Experimental results indicate that the best estimates of roundness obtained using the four methods are 0.629,0.221,0.616,and 0.608 μm,with corresponding standard uncertainties of 0.099,0.138,0.103,and 0.094 μm,respectively;among them,the minimum zone method yields the lowest uncertainty.Random Forest analysis further reveals that the error component associated with probe wear exerts the most significant influence in the least squares,mini-mum circumscribed circle,and minimum zone methods,with total scores of 0.74,4.50,and 0.53,re-spectively.By integrating the classical GUM-MCM uncertainty evaluation framework with a Random For-est regression model,the proposed approach effectively verifies the reliability of roundness measurements performed by micro/nano CMMs while quantitatively resolving the contributions of individual uncertainty sources.These findings provide important engineering insights for improving the accuracy and reliability of measurements in ultra-precision manufacturing.