基于刚度分析的机器人铣削加工刀具角度优化

Optimization of Tool Angle in Robot Milling Based on Stiffness Analysis

为提高多轴机器人铣削的加工精度,提出一种新型的刀具方向角优化方法。该方法综合考虑了串联机构的固有特性及其与机器人刚度的关系,从而在生成精加工刀具方向角时选择最佳的机器人姿势。由于在不改变刀具轨迹的情况下,通过优化选择刀具的方向角来减少加工误差,该优化方法无需修改原始刀具轨迹以便补偿预测偏差。在多轴铣削机器人系统上的实验结果验证了该方法的有效性。研究结果表明,该方法能够加工出具有精细表面的三维形状,并减少了由于刀具向机器人刚度最低方向位移所引起的偏差。相比基于体积刚度性能指标的刀具方向角优化方法,RMS误差减少了0.05 mm。

In order to improve the machining accuracy of multi-axis robot milling,a new method of optimizing tool orientation angle was proposed.The inherent characteristics of the series mechanism and its relationship with the robot stiffness were comprehensively considered,so that the best robot posture is selected when generating the azimuth of the finishing tool.A one-way stiffness performance index was proposed to evaluate the stiffness of the robot.Because the machining error was reduced by optimizing the direction angle of the selected tool without changing the tool trajectory,the proposed method is significantly less convoluted than conventional optimization methods.The efficacy of the proposed method was validated experimentally using a multi-axis milling robot.The results show that,this method can process three-dimensional shapes with fine surfaces and reduce the deviation caused by the displacement of the tool in the direction of the lowest stiffness of the robot.Compared with the tool direction angle optimization method based on the volume stiffness performance index,the RMS error is reduced by 0.05 mm.