数控机床热误差建模及预测方法分析
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摘要
热误差作为制约数控机床加工精度的关键因素,在重型数控机床上表现得尤为明显。以重型落地镗铣床为例,根据热误差测量试验数据,分析重型数控机床温度场特性,并基于兼顾相关系数和欧式距离的系统聚类准则,对温度测点系统进行优化,以减小温度测点间共线性。通过优化温度测点,采用多元线性回归分析,建立重型数控机床热误差预测模型。由现场试验可知,建立的热误差预测模型可将均方根误差控制在10μm以内,有效地提高了热误差预测精度。
As a key factor restricting the machining accuracy of computer numerical control(CNC) machine tools, thermal error is especially obvious in heavy CNC machine tools. Taking heavy-duty floor boring and milling machine as an example, the temperature field characteristics of heavy-duty CNC machine tools are analyzed according to the thermal error measurement data.The temperature measurement point system was optimized based on the system clustering criterion considering both the correlation coefficient and Euclidean distance to reduce the collinearity between temperature measurement points. According to the optimized temperature measurement point, the thermal error prediction model of heavy CNC machine tool was established by multiple linear regression analysis. The field test shows that the thermal error prediction model can control the root mean square error within 10 micron and improve the thermal error prediction accuracy effectively.
As a key factor restricting the machining accuracy of computer numerical control(CNC) machine tools, thermal error is especially obvious in heavy CNC machine tools. Taking heavy-duty floor boring and milling machine as an example, the temperature field characteristics of heavy-duty CNC machine tools are analyzed according to the thermal error measurement data.The temperature measurement point system was optimized based on the system clustering criterion considering both the correlation coefficient and Euclidean distance to reduce the collinearity between temperature measurement points. According to the optimized temperature measurement point, the thermal error prediction model of heavy CNC machine tool was established by multiple linear regression analysis. The field test shows that the thermal error prediction model can control the root mean square error within 10 micron and improve the thermal error prediction accuracy effectively.
引文
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[7]郑素娟,黄美发,张奎奎,等.多工况下数控机床主轴热误差建模[J].组合机床与自动化加工技术,2017(7):27-31.ZHENG S J,HUANG M F,ZHANG K K,et al.Thermal Error Modeling of CNC Machine Tools under Multiple Working Conditions[J].Modular Machine Tool and Automatic Machining Technology,2017(7):27-31.
[8]邬再新,吴永伟.模糊神经网络在精密卧式加工中心热误差的预测[J].组合机床与自动化加工技术,2017(8):51-54.WU Z X,WU Y W.Prediction of Thermal Error in Precision Horizontal Machining Center by Fuzzy Neural Network[J].Combination Machine Tool and Automatic Machining Technology,2017(8):51-54.
[2]余文利,姚鑫骅,孙磊,等.基于PLS和改进CVR的数控机床热误差建模[J].农业机械学报,2015,46(2):357-364.YU W L,YAO X H,SUN L,et al.Thermal Error Modeling of CNC Machine Tools Based on PLS and Improved CVR[J].Journal of Agricultural Machinery,2015,46(2):357-364.
[3]张恩忠,齐月玲,冀世军,等.基于支持向量回归机的精密数控平台热误差建模与补偿研究[J].组合机床与自动化加工技术,2017(4):48-51.ZHANG E Z,QI Y L,JI S J,et al.Thermal Error Modeling and Compensation of Precision CNC Platform Based on Support Vector Regression Machine[J].Modular Machine Tool and Automated Machining Technology,2017(4):48-51.
[4]苗恩铭,徐建国,吕玄玄,等.数控机床工作台误差综合补偿方法研究[J].中国机械工程,2017,28(11):1326-1332.MIAO E M,XU J G,LV X X,et al.Research on Error Compensation Method of CNC Machine Tool Table[J].China Mechanical Engineering,2017,28(11):1326-1332.
[5]李杰,谢福贵,刘辛军,等.五轴数控机床空间定位精度改善方法研究现状[J].机械工程学报,2017,53(7):113-128.LI J,XIE F G,LIU X J,et al.Research Status of Improvement Methods for Spatial Positioning Accuracy of Five-axis NC Machine Tools[J].Journal of Mechanical Engineering,2017,53(7):113-128.
[6]王洪乐,王家序,周青华,等.基于BP神经网络的数控机床综合误差补偿方法[J].西安交通大学学报,2017,51(6):138-146.WANG H L,WANG J X,ZHOU Q H,et al.Comprehensive Error Compensation Method for CNC Machine Tools based on BP Neural Network[J].Journal of Xi'an Jiaotong University,2017,51(6):138-146.
[7]郑素娟,黄美发,张奎奎,等.多工况下数控机床主轴热误差建模[J].组合机床与自动化加工技术,2017(7):27-31.ZHENG S J,HUANG M F,ZHANG K K,et al.Thermal Error Modeling of CNC Machine Tools under Multiple Working Conditions[J].Modular Machine Tool and Automatic Machining Technology,2017(7):27-31.
[8]邬再新,吴永伟.模糊神经网络在精密卧式加工中心热误差的预测[J].组合机床与自动化加工技术,2017(8):51-54.WU Z X,WU Y W.Prediction of Thermal Error in Precision Horizontal Machining Center by Fuzzy Neural Network[J].Combination Machine Tool and Automatic Machining Technology,2017(8):51-54.