数控机床几何误差与热误差综合建模及其实时补偿

为提高数控机床的精度,提出一种数控机床的几何与热的复合误差综合建模方法。通过分析机床在不同温度状态下的误差数据,得到机床误差分布规律;根据几何误差和热误差的不同特性进行误差分离,采用多项式拟合与线性拟合方法建立机床几何误差与热误差的综合数学模型;利用数控(Computer numerical control,CNC)系统的外部机床坐标系偏置功能,应用自行研发的综合误差实时补偿系统进行误差在线实时补偿。该误差补偿方法综合考虑机床几何误差及其在机床不同温度下的变化,全面分析整个温升过程直至热稳态的误差及其变化规律。经检测认证表明,应用该误差补偿方法及其实时补偿系统可使机床在常温下的定位误差由44.1μm降低到3.6μm,补偿91.8%;温升之后的定位误差由26.0μm降低到5.1μm,补偿80.4%,大幅度提高机床的精度。

Synthesis Modeling and Real-time Compensation of Geometric Error and Thermal Error for CNC Machine Tools

In order to improve the machine accuracy,a synthesis modelling method of geometric and thermal error is presented.Machine error distribution law is obtained through the analysis of machine error data at varying temperatures.Based on the different characteristics of geometric error and thermal error,error separation is carried out.Synthesis mathematical model for geometric and thermal error is proposed by using polynomial fitting and linear fitting.Online real-time error compensation is implemented by applying the computer numerical control(CNC) external machine coordinate system shift function and a novel developed synthesis error real-time compensation system.This error compensation method concerns the geometric error and its variations at different temperatures,thus a comprehensive analysis is made on the error and its regularity in the overall temperature rise to the heat steady-state.The inspection certificates that the maximum positioning error in normal temperature is reduced from 44.1 μm to 3.6 μm by applying the error compensation method and real-time compensation system,which is compensated 91.8% compared with no compensation.After the temperature rise,the maximum positioning error in normal temperature is reduced from 26.0 μm to 5.1 μm,which is compensated 80.4% compared with no compensation.The machine accuracy is effectively improved.