针对五轴联动数控机床的位置与姿态误差补偿过程中各运动轴的误差补偿量与刀具和工件间的误差值耦合关系较为复杂的问题,在解析五轴机床运动学方程的基础上,利用多轴机床的误差运动学原理,建立了用各运动轴坐标系变换矩阵描述的机床误差模型。基于小误差补偿运动假设,分析了误差运动和补偿运动间的相互关系,对五轴机床各运动轴的位置与方向的误差补偿运动进行了解耦,建立了五轴数控机床的一种新的空间几何误差补偿模型和补偿算法。基于此算法开发了具有空间补偿功能的后处理模块,并通过实验验证了该模块在提高机床加工精度方面的有效性。
Aiming at the problem that the position and orientation error compensation of a five-axis machine tool is more complicated because of the complex coupled effects between the joint variables and the position/orientation of the tools and work-piece, the paper gives a volumetric error model by using the coordinate transformation method on the basis of analyzing the kinematics equations of five-axis machine tools and multi-axis machine tools' error kinematics principle. Based on the rigid body kinematics with small error assumption and the analysis of error motions and the compensation motions, a new volumetric error compensation model and a compensation algorithm are presented by deeoupling the error compensation motions, thus the position and orientation compensation values of the joint variables can be obtained finally with the model. A new post-processing module was created by the compensation algorithm, and it was tested by experiment with the five-axis machine tools and the experimental results show that the machining accuracy can be improved effectively when using it.