Inverse dynamic analysis of milling machining robot: Application in calibration of cutting force

Abstract

This article presents analysis of inverse dynamics of a serial manipulator in milling process. With the exception of positioning accuracy issue, machining by robots have more advantages than by conventional CNC milling machines, due to higher flexible kinematics (many links and degrees of freedom) and larger working space. Therefore, motion of the robot links is more complicated. Process forces and complicated motion involve to difficulties in solving dynamic problems of robots. This affects the robot control to match machining requirements. This article utilizes the transformation coordinates and the homogeneous transformation matrices to analysis of kinematics and dynamics of the robot. In general, cutting forces are determined by using empirical formulas that lead to errors of cutting force values. Moreover, the cutting forces are changing and causing vibration during machining process. Errors of cutting force values affect the accuracy of the dynamic model. This paper proposes an algorithm to compute the cutting forces based on the feedback values of the robot's motion. The results of kinematic and dynamic simulation of the computing program and calibrating cutting force prove intuitively and reliably validation of the proposed method.