CAD/CAM-based position/force controller for a mold polishing robot

Control of robotic mold polishing is considered in this paper. CAD/CAM-based position/force controller that simultaneously performs stable force control and exact pick feed control along curved surface is presented for a mold polishing robot. The force feedback loop controls the polishing force consisting of the contact and kinetic friction forces. During the mold polishing, the position feedback loop has a delicate contribution to the force feedback loop in Cartesian space so that the abrasive tool does not deviate from the desired trajectory and keeps a constant pick feed, e.g., 0.2 mm. When the robot with the CAD/CAM-based position/force controller runs, cutter location (CL) data with normal vectors, called multi-axis CL data, are used for not only a desired trajectory of tool translational motion but also desired contact directions given to a mold. The multi-axis CL data allow the mold polishing robot to realize a complete non-taught operation of the position and contact direction. The experimental results show that the CAD/CAM-based position/force control method achieves successful robotic mold polishing with curved surface.