面向铣削机器人的低成本精确标定及刀路拟合方法

Low Cost Accurate Calibration and Tool Path Fitting Method for Milling Robot

针对铣削机器人路径轨迹绝对拟合精度低及空间路径拟合会产生刀路误差的问题,提出了一种无须精密仪器即可获得有效标定的方法。研究重点在于提高铣削加工精度。首先,通过重新计算和修正机器人路径轨迹控制点的方式,解决了路径拟合带来的切削误差问题,为接下来的切削测量精度提供了进一步的保障;然后,针对铣削主轴使工具末端位置产生的偏移,在机器人标定模型中加入了自重及外加负载模型,并且特别引入了包含角度数据的约束方程和目标函数,增加了标定数据的全面性并提高了标定效率;最后,利用此方法对KUKA60机器人进行参数标定实验,实验显示,经过标定后的铣削机器人的加工精度得到了显著的提高,铣削方块边长和夹角精度分别从0.520 mm和30分降为0.240 mm和16分,提高了53.8%和46.7%。

Aiming at the problems of low accuracy of absolute path fitting of milling robot and tool path error caused by spatial path fitting,a method for obtaining effective calibration without precision instrument is proposed.This paper focuses on improving the machining accuracy of milling.Firstly,the cutting error caused by path fitting is solved by recalculating and revising the control points of robot path trajectory,which provides further guarantee for the following cutting measurement accuracy.Secondly,the self-gravity and external load model are added into the robot calibration model because of the offset of tool end position caused by milling spindle.And the constraint equation and objective function containing angle data are introduced to increase the comprehensiveness of calibration data and improve the calibration efficiency.The proposed method is used to calibrate the para-meters of Kuka60 robot.Experiments show that the machining accuracy of calibrated robot improves significantly.The accuracy of milling block distance and angle decreases from 0.520 mm and 30 min to 0.240 mm and 16 min respectively,and the milling accuracy increase by 53.8%and 46.7%.