基于机床运动模型的走刀步长计算方法

为提高五坐标数控加工刀具轨迹生成的精度和切削效率，通过特定机床结构运动建模，对自由曲面刀具轨迹规划中的走刀步长计算方法进行研究。针对刀具摆动与工作台转动类型的非正交结构五坐标机床，在建立机床运动传递关系的基础上，实现任意刀轴方位的机床各轴运动坐标分解，构建机床运动模型。基于此，分析切削误差产生机理，推导出非正交结构的机床实际运动误差估计公式。利用切削误差对比关系，迭代计算满足精度要求的最大走刀步长。算例表明，在相同的允许误差条件下，本文算法较之传统变步长方法，最大误差降低了37.01%，而平均步长相对于等步长方法，增加了8.91%，说明基于机床运动模型的走刀步长计算方法能够有效控制切削误差，并提高自由曲面五坐标加工的刀具轨迹质量。

Calculation Method for Step Length Based on the Kinematics Model of Machine Tools

To improve the precision and cutting efficiency of the tool path generation in five-axis NC machining of sculptured surfaces, through kinematic modeling of the special machine tools, a new calculation method for step length is presented. Aiming at five-axis NC machines with non-orthogonal structure of tool swinging and table rotation type, the kinematic model including the establishment of the motion transmission and the decomposition of the motion coordinate is constructed. And then, it is shown that the c...