转台-摆头式五轴机床几何误差测量及辨识

为降低转动轴几何误差对转台-摆头式五轴机床精度的影响,提出了基于球杆仪的位置无关几何误差测量和辨识方法。基于多体系统理论及齐次坐标变换方法建立了转台-摆头式五轴机床位置无关几何误差模型,依据旋转轴不同运动状态下的几何误差影响因素建立基于圆轨迹的四种测量模式,并实现10项位置无关几何误差的辨识。利用所建立的几何误差模型进行数值模拟,确定转动轴的10项位置无关几何误差对测量轨迹的影响。最后,采用误差补偿的形式实验验证所提出的测量及辨识方法的有效性,将位置无关几何误差补偿前后的测量轨迹进行比较。误差补偿后10项位置无关几何误差的平均补偿率为70.4%,最大补偿率达到88.4%,实验结果表明所提出的建模和辨识方法可用于转台-摆头式五轴机床转动轴精度检测,同时可为机床精度评价及几何精度提升提供依据。

Measurement and identification of geometric errors for turntable-tilting head type five-axis machine tools

In order to reduce the influence of the geometrical error of rotary axis on the accuracy of turntable-tilting head type five-axis machine tools, a Position-Independent Geometric Error(PIGE) measurement and identification method based on the measurement of the Double Ball Bar(DBB) is proposed. Firstly, based on multi-body system theory and homogeneous coordinate transformation method, the position-independent geometric error model of turntable-tilting head type five-axis machine tool position was established. Four measurement model based on circular path measurement were established according to the influence factors of geometric errors under different motion states of rotary axes, and 10 position-independent geometric errors were identified. Secondly, the numerical simulation was carried out by using the established geometric error model to quantify the influence of 10 geometric errors on the measurement trajectory of the rotary axes. Finally, the geometric error compensation was conducted to validate the validity of the proposed measurement and identification methods, and the measurement trajectories before and after the position-independent geometric error compensation were compared. The average compensation rate of the position-independent geometric errors of the 10 positions is 70.4%, and the maximum compensation rate is 88.4%. The experimental results show that the proposed modeling and identification method can be used to detect the accuracy of rotary axis, at the same time which can be used for the machine tool accuracy evaluation and provide the guidance for improving the accuracy.