考虑主轴刀柄结合面特性的机器人铣削系统刀尖频响预测研究

Aiming at the problems that the tool tip frequency response of robot milling systems was posture-dependent, which made it difficult to accurately predict the stability and effectively control the machining chatters in the process of robot pose changing, a prediction method of the tool tip frequency response of robot milling systems was proposed considering the contact stiffness of spindle-toolholder interface. Based on Euler-Lagrangian method and unit area method of Yoshimura, the dynamics model of robot body and the contact stiffness model of spindle-toolholder interface were constructed, respectively. Then, based on the theory of the main and auxiliary degrees of freedom of finite element, the dynamics model of robot body and the contact stiffness model of spindle-toolholder interface were combined to construct the prediction model of tool tip frequency response of robot milling systems. The verification test of tool-tip frequency response prediction under different postures of the robot was carried out. The results show that the maximum error of the natural frequency is as 6.63% and the maximum error of the corresponding amplitude is as 9.80% compared with the frequency response function of tool-tip obtained by simulations and experiments, which verifies the accuracy of the proposed prediction model and proves that the model may realize accurate prediction of frequency response function under any postures of the robot.