A new compensation method for geometry errors of five-axis machine tools
A new compensation method for geometry errors of five-axis machine tools
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DOI：
10.1016/j.ijmachtools.2006.03.008
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发表时间：
2007-02
影响因子：
14
通讯作者：
Y. Hsu;S. S. Wang-S.
中科院分区：
文献类型：
--
作者：
Y. Hsu;S. S. Wang-S.
本文旨在建立一种新的五轴机床几何误差补偿方法。在五轴机床的运动坐标变换中，刀具的方位由机床旋转轴的运动位置决定，而刀尖的位置则由机床直线轴和旋转轴共同决定。此外，由于工件坐标与机床坐标之间存在非线性关系，工件坐标系中的误差与机床坐标系中的误差不直接相关。因此，本研究发展了一种新的补偿方法，解耦法，五轴机床的几何误差。提出的方法是基于一个模型，认为刀具定位误差只涉及到运动的机器旋转轴，它进一步计算的旋转轴和线性轴的误差补偿分开，而不是传统的方法同时计算它们，即确定补偿的机器旋转轴，然后计算补偿与机器线性轴。最后，将该补偿机制应用于CAM系统的后置处理中，并在真实的机床加工中使用补偿后的NC代码对误差补偿的有效性进行了评价。与以往的补偿方法相比，本补偿方法具有简单、直观、模型无奇异点等特点。结果表明，定位精度提高了8-10倍。因此，本研究所提出之补偿机制可有效地补偿五轴加工机之几何误差。
The present study aims to establish a new compensation method for geometry errors of five-axis machine tools. In the kinematic coordinate translation of five-axis machine tools, the tool orientation is determined by the motion position of machine rotation axes, whereas the tool tip position is determined by both machine linear axes and rotation axes together. Furthermore, as a nonlinear relationship exists between the workpiece coordinates and the machine axes coordinates, errors in the workpiece coordinate system are not directly related to those of the machine axes coordinate system. Consequently, the present study develops a new compensation method, the decouple method, for geometry errors of five-axis machine tools. The method proposed is based on a model that considers the tool orientation error only related to motion of machine rotation axes, and it further calculates the error compensations for rotation axes and linear axes separately, in contrast to the conventional method of calculating them simultaneously, i.e. determines the compensation of machine rotation axes first, and then calculates the compensation associated with the machine linear axes. Finally, the compensation mechanism is applied in the postprocessor of a CAM system and the effectiveness of error compensation is evaluated in real machine cutting using compensated NC code. In comparison with previous methods, the present compensation method has attributes of being simple, straightforward and without any singularity point in the model. The results indicate that the accuracy of positioning was improved by a factor of 8–10. Hence, the new compensation mechanism proposed in this study can effectively compensate geometry errors of five-axis machine tools.