Robot Flexible Polishing Methods for Curved Mold and Adaptive Impedance Control

Abstract

In the automatic polishing process by industrial robot, the curvature variation at the polishing point will cause the problem of uneven polishing quality. To solve the problem, polishing methods based on constant down displacement and constant downforce are analyzed according to elliptical Hertzian contact theory. Then, the constant stress polishing methods based on displacement and force are proposed. Simulations are performed by finite element analysis software. The stress changes of four polishing methods during the polishing process are compared. Finally, a force control strategy based on speed regulation and impedance control algorithm is adopted to ensure the stability of the tool and workpiece contact during machining. The results show that stable polishing stress can be obtained by the constant stress polishing methods based on down displacement and downforce. Therefore, it is feasible to control the uniformity of polishing quality by adjusting the displacement or downforce of an industrial robot.