机器人轨迹跟踪精度对铣削再生颤振的影响

Influence of Robot Trajectory Tracking Accuracy on Milling Regenerative Chatter

针对工业机器人低轨迹精度导致的轨迹跟踪误差,分析了切削过程中动态切削厚度和时滞效应对轨迹跟踪误差的响应。考虑轨迹跟踪误差引起的加工底面过程阻尼增加现象,建立包含轨迹误差的动态切削力模型。通过铣削实验验证了该模型,发现了机器人轨迹跟踪误差引发的动态切削厚度变化、时滞效应以及过程阻尼增加等现象能够提高临界轴向切深,扩大铣削加工的稳定域,但会降低表面质量与尺寸精度。本文的理论模型解释了在机器人铣削实验过程中出现的颤振发生又逐渐消失的特殊现象,为提高机器人铣削效率及抑制铣削颤振提供了理论模型。

Aiming at the trajectory tracking error caused by the low trajectory accuracy of industrial robots,the responses of dynamic cutting thickness and time delay during cutting to the trajectory tracking error are analyzed.Taking the increase in process damping of the bottom caused by trajectory tracking error into consideration,a dynamic cutting force model including the trajectory error is developed.The model is verified by milling experiments,and it is found that the change of dynamic cutting thickness,the time delay effect,and the increase in process damping caused by the trajectory tracking error of the robot,can increase the critical axial depth of cutting and improve the stability range of milling,and will decrease the surface quality and dimensional accuracy.The proposed theoretical model explains the special phenomenon that the chatter occurs and then disappears in the robot milling experiment,can serve as a theoretical model for improving the robotic milling efficiency and suppress the milling chatter.