Modeling and Stability Analysis of Robot-assisted Thin-walled Milling

Abstract

Thin-walled machining has played an important role in automotive and aerospace domains. Due to physical characteristics of the flexible structure, the thin-walled machining is prone to the deformation and the onset of chatter. To solve the problem, a robot is considered to support the flexible workpiece while cutting. This paper studies finite element dynamic modeling and stability analysis of the robot-assisted thin-walled milling system. It is divided into three submodels: thin-walled workpiece, robot, and cutting process. The finite element method (FEM) is adopted to obtain a realistic dynamic model of the workpiece and allows analysis of any location. The robot dynamics is linearized to a 1-degree-of-freedom (DOF) mass-spring-damper system for model reduction. The cutting force variation and the regenerative effects involved in the cutting process establish time-periodic and time delay terms in the milling model. The semi-discretization method (SDM) is used for the stability analysis. Simulation results show a significant improvement in the milling stability from the robot support in any location, leading to higher productivity.