基于多体系统理论的数控机床加工精度几何误差预测模型

Geometric error prediction model of machining accuracy of machine tools based on multi-body system theory

针对多轴联动数控机床加工精度误差补偿问题,从分析数控机床误差产生机理和建立精度误差补偿模型的角度,提出了基于多体系统理论的数控机床加工精度几何误差预测模型。分析了B-A摆头五轴龙门数控机床的拓扑结构关系、低序体阵列、各典型体坐标变换,推导出了B-A摆头五轴龙门数控机床精度几何误差预测函数。采用平动轴十二线法误差参数辨识算法,测量并计算了某B-A摆头五轴数控机床21项空间几何误差,为精度几何误差预测函数提供有效参量。该几何误差参数建模方法,对不同拓扑结构和运动关系的数控机床具有通用性,为后续数控机床误差动态实时补偿并提高切削加工精度提供了理论依据。

.As for the problem that machining accuracy of multi-axis CNC machine tools is compensated,it is proposed in this paper that the method of CNC machine tools machining accuracy geometric error prediction model is based on multi-body system theory,from the point of view that the analysis of CNC machine tools error generation mechanism and building precision error compensation model. Topological relationships,the low-order body arrays and coordinate transformation of typical body of the B-A pendulum angles gantry CNC machine tools are researched in the paper. The precision error prediction function of the B-A pendulum angles gantry CNC machine tools is deduced. 21 space geometry errors of the CNC machine tools are measured and calculated by using 12 lines error identification algorithm of motion axis.Effective error parameters are offered for the precision error prediction function. The method of building precision error model is versatile for CNC machine tools of different topological structures and movement relation,and it offers theoretical basis for error dynamic real-time compensation and enhancing machining precision of CNC machine tools.