Cleaning robot for carbon anode block based on vision inspection and hybrid force/position control

A cleaning robot was designed to clear up mounting holes of carbon anode used in aluminium electrolysis process. Machine vision system consists of charge coupled device (CCD) camera and optical inspection system was installed on the robot to obtain accurate centre position of four holes on one carbon workpiece. For mounting anode rods stably, each hole has helical grooves inside the inner wall. The cleaning tool with double spindle was special designed to be capable of clearing up the wall, sub-face and grooves of the mounting hole in one feeding process along the height direction. The tool was equipped on the end of guide rail of Z-direction of the robot which center can be located to the centre of holes accurately when utilizing precision slide guide and ball screw. Force sensors were used to inspect the contact force of shaping milling cutter on main shaft and the torque of slotting tool on auxiliary shaft. Force/position control was used during the cleaning process to make the slotting tool adjust itself automatically along the spiral grooves and maintain the contact forces stable, which is similar with form copying method.