基于克里金插值的机床空间误差测量与补偿方法研究

Spatial error measurement and compensation of CNC machine tool based on Kriging interpolation

提出了一种基于克里金插值的机床空间误差测量与补偿方法。机床加工精度一般受切削力、热变形和空间误差的影响,为采集机床空间误差样本,提出了一种基于克里金插值的测量方法,利用激光跟踪仪测量给定点的空间误差,通过克里金插值计算给定点之间的空间误差,并进行了机床空间误差测量实验。结果表明,克里金插值的计算精度明显高于线性插值,有效提高了空间误差测量精度。为实施空间误差补偿,通过对机床误差模型进行分步解耦,开发了空间误差补偿器,并进行了机床空间误差补偿实验。结果表明,机床主轴在X轴方向的变形量为025μm,实施空间误差补偿后,某工件平面加工后的最大轮廓误差由15μm减小到了5μm。该补偿方法为提高数控机床的加工精度提供了一种有效途径。

A spatial error measurement and compensation method based on Kriging interpolation and DSP was explored for a CNC machine tool. The spatial accuracy of machine tool is mainly affected by cutting force,thermal deformation and geometric error sources. In order to collect spatial error samples,a new method based on Kriging interpolation was proposed in this paper,and a laser tracker is used for measuring the spatial error of given points on CNC machine tool,and Kriging interpolation is applied to the spatial errors calculation among measurement points. A spatial error measurement experiment was proceeded on a CNC machine tool. In order to fulfill spatial error compensation,an ordinal decoupling compensation method was proposed,and a spatial error compensator based on DSP was designed for compensation experiment of the CNC machine tool. The experiment results shows the spindle deformation of CNC machine tool in X direction is 025μm,and the maximum profile error of plane part is reduced from 15 μm to 5 μm after compensation. The proposed spatial error compensation method provides an effective way for improving machining accuracy of CNC machine tool.