Analysis of Tool Tip Dynamic Characteristics and Stability Prediction for Robotic Milling Tasks

doi:10.3901/JME.2022.17.261

Abstract

Abstract: The machining vibration is easy to occur in the robotic milling process due to the low stiffness of robot structure, the complex configuration of robotic end load and local weak rigidity of workpiece, which seriously affects the machining surface quality. Robotic milling stability mainly depends on the dynamic characteristic of the tool tip, therefore a tool tip frequency response function (FRF) prediction method for robot milling tasks is proposed, which could predict the tool tip FRF at any robot posture to realize the stability prediction of robotic milling process, then the workpiece machining quality could be largely improved by optimizing the process parameters. Firstly, the experimental amount is reduced and the requirements for experimental postures are lowered by introducing the nonlinear least square weighted superposition method. Then the tool tip FRF of robot at any target posture in a certain workspace can be predicted by giving the tool tip FRF of any amount of benchmark experimental postures. Furthermore, a linearized modal parameter superposition method is proposed to avoid the multi-mode phenomenon caused by the direct superposition of FRF, which could largely improve the prediction accuracy. Finally, the accuracy and practicability of the model are verified by robot milling experiments, and then the workpiece machining quality is largely improved by the further optimization of the robotic milling process parameters.

Key words: milling stability, machining posture, regenerative chatter, frequency response function, modal aliasing

CLC Number:

TP242
TH161

YE Songtao, YAN Sijie, LI Wentao, XU Xiaohu, LU Jialin. Analysis of Tool Tip Dynamic Characteristics and Stability Prediction for Robotic Milling Tasks[J]. Journal of Mechanical Engineering, 2022, 58(17): 261-275.

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