The thermal induced errors can account for as much as 70% of the dimensional errors on a workpiece. Accurate modeling of errors is an essential part of error compensation. Base on analyzing the existing approaches of ...The thermal induced errors can account for as much as 70% of the dimensional errors on a workpiece. Accurate modeling of errors is an essential part of error compensation. Base on analyzing the existing approaches of the thermal error modeling for machine tools, a new approach of regression orthogonal design is proposed, which combines the statistic theory with machine structures, surrounding condition, engineering judgements, and experience in modeling. A whole computation and analysis procedure is given. Therefore, the model got from this method are more robust and practical than those got from the present method that depends on the modeling data completely. At last more than 100 applications of CNC turning center with only one thermal error model are given. The cutting diameter variation reduces from more than 35 μm to about 12 μm with the orthogonal regression modeling and compensation of thermal error.展开更多
大型龙门五轴机床的热变形是影响加工精度的重要因素之一。文章探讨了环境温度变化对机床热变形的影响规律。为提升大型龙门数控机床环境综合热误差预测精度,设计了一种基于带卷积的灰色长短期记忆神经网络(grey long short-term memory...大型龙门五轴机床的热变形是影响加工精度的重要因素之一。文章探讨了环境温度变化对机床热变形的影响规律。为提升大型龙门数控机床环境综合热误差预测精度,设计了一种基于带卷积的灰色长短期记忆神经网络(grey long short-term memory neural network, CNN-GreyLSTM)的热误差预测模型。以某大型龙门机床为研究对象,使用有限元仿真与试验相结合的方式分析了环境温度变化引起的刀尖点热漂移误差。分别采用CNN-Grey-LSTM、CNNLSTM和带卷积积分的灰色神经网络模型(GNNMCI(1,N))建立热误差模型并进行对比分析。结果表明,与常见的神经网络相比,CNN-Grey-LSTM模型能更好适应复杂多变的数据特征和时间序列预测问题,体现出更好的预测精度与鲁棒性。展开更多
文摘The thermal induced errors can account for as much as 70% of the dimensional errors on a workpiece. Accurate modeling of errors is an essential part of error compensation. Base on analyzing the existing approaches of the thermal error modeling for machine tools, a new approach of regression orthogonal design is proposed, which combines the statistic theory with machine structures, surrounding condition, engineering judgements, and experience in modeling. A whole computation and analysis procedure is given. Therefore, the model got from this method are more robust and practical than those got from the present method that depends on the modeling data completely. At last more than 100 applications of CNC turning center with only one thermal error model are given. The cutting diameter variation reduces from more than 35 μm to about 12 μm with the orthogonal regression modeling and compensation of thermal error.
