数控机床转动轴进给系统轮廓误差分析

在五轴联动数控机床中,转动轴进给系统的动态精度对轮廓误差的影响是不可忽视的。采用不同空间位置上的外形轮廓,对五轴联动数控机床转动轴的联动运动产生的轮廓误差进行分析。在建立转动轴进给系统模型的基础上,利用刀具位置系统到加工系统的转换得到转动轴指令,通过进给系统动态误差模型得到仿真输出指令,再将输出指令从加工系统转换回刀具位置系统,比较刀具位置的偏差,从而得到轮廓误差。找出轮廓误差点与外形轮廓空间位置之间的对应关系,利用这种关系可快速通过轮廓误差来考察转动轴进给系统的动态性能,为机床快速调整和维修提供一种手段。

Contour Error Analysis for Rotation Feed Axis in CNC Machines

As one axis of five-axis CNC machines,rotary axis servo system dynamic performance impacts heavier on the contour accuracy than that of linear axes and has to be treated carefully.Herein,the servo system model of axis rotation was established firstly.The rotation axis commands were formed based on the conversion system from the tool position to processing system,the output instructions were related to the servo system dynamic error model,and then the output instructions from the processing system were converted back to the tool position system.The deviation was given from comparing the position of the tool with the designing surface and the contour errors were shown.A series of points on the contour were selected to calculate the errors from the joint motion of rotation axis in the five-axis CNC machine.The relation between the points with biggest departure and the geometric characteristics were analyzed.It may be used to evaluate the dynamic errors from rotation axis rapidly for adjustment and maintenance of CNC machines.