五轴机床误差建模与补偿解析新算法

A New Synthesis Error Modeling and Compensating Algorithm of the Five-axis Machine Tools

为了建立高精度的五轴机床综合误差补偿模型,假设机床各部件为刚体连接,简化了机床运动拓扑关系,并解析了59项综合误差分量。基于小误差假设,运用多体动力学对机床几何误差和热误差统一建模,提出了新型综合误差补偿模型。综合机床各轴热误差解析结果,提出了针对主轴热误差和进给轴热误差的新型测量法:5点测量法和6点测量法。考虑到机床热误差测量点分布离散且数据信息不完整,运用灰色系统理论建立了变权系数GM(1,n)热误差预测模型,并完成了热误差曲线拟合。实验证明理论预测值与实验结果一致,主轴模型误差范围在0～2μm之间,进给轴模型误差在0～12μm之间。将该算法用SIMEMS840D数控系统中的PMC单元开发实时补偿软件,实验表明机床在完成补偿后误差变化量在0～29μm之内。

In order to construct the high precision error compersation model,the topological relationship of machine kinematics was simplified and 59 independent error components were analyzed. Based on the rigid body kinematics with small error assumption,a new comprehensive error model with geometric error and thermal error was given. A new thermal error measurement method was proposed based on the thermal error analysis. Five-point method was used to measure the spindle thermal error. Six-point method was used to measure the feed axis thermal error. Considering error measurement point discrete and incomplete,with the variable weights GM（ 1,n）,the thermal error model was proposed to pradict grey thermal error data. The experimental results showed that the spindle model error range was between 0～ 2 μm,and the feed axis model error range was between 0 ～ 12 μm. Theoretical prediction curves were consistent with the experimental results. A CNC real-time compensation software was developed with SIMEMS840D controller＇s PMC program based on above error model.After the compensation,the machine tool error range was between 0 ～ 29 μm.