针对现有刀具姿态控制方法不能保证加工中刀轴矢量平滑变化,造成旋转轴速度、加速度的不连续以及加工精度低、表面不光滑等问题,在分析刀轴矢量变化与旋转轴速度、加速度平滑性间关系的基础上,提出一种能够保证加工中旋转轴速度、加速度连续的刀轴矢量平滑插补算法。该算法先依据给定首末刀轴矢量建立局部旋转坐标系;在已建立的局部旋转坐标系中采用倾斜角和射影角来表示刀具姿态曲线;依据刀具姿态曲线的二阶连续性对倾斜角和射影角表达式进行求解。算法仿真和实际验证结果表明,本算法能够保证加工中刀具姿态曲线经过程序给定刀轴矢量,在产生较小刀具姿态误差的同时,保证加工中旋转轴速度、加速度连续。
Currently existing tool posture control methods can't ensure the smooth motion of tool orientation, which may result in discontinuity of velocity and acceleration of rotation axes and may bring about problems of low accuracy and rough surface. In order to solve these problems, a tool orientation smooth interpolation algorithm that can make velocity and acceleration of rotation axes continuous is proposed. In this algorithm, local rotating coordinate systems are established according to the start and the end tool orientation vectors of each segment. The orientation spline of each segment can be indicated as a function of tilt angle and projection angle. The property of C2 continuity of the orientation spline can then be used for solving the tilt angle and projection angle. The feasibility and the effectiveness of the algorithm are tested by simulated examples. The results show that the algorithm can ensure the continuity of velocity and acceleration of rotation axes.