Position/force control and its application to open architectural industrial robots

In this chapter, a position/force control system is first designed for industrial robots with an open architecture controller. Position and orientation of the tool attached to the tip of an industrial robot are controlled based on the model designed by a CAD system. Also, force including kinetic friction is controlled through a desired impedance model. The both manipulated variables generated from the position control system and force control system are velocity quantity in Cartesian-coordinate system, so that the hybrid control system can be easily applied to industrial robots with an open architecture controller. Next, we introduce two examples of applications being utilized in actual manufacturing process. One is the 3D robot sander which sands the free-formed surface of wooden materials. The finished wooden workpiece with curved surface is used for a part constructing a piece of artistic furniture. The other is the mold polishing robot which finishes aluminum PET bottle blow molds. Further, the application limit of articulated-type industrial robots is quantitatively evaluated through a simple static position/force measurement. Finally, we consider a novel desktop orthogonal-type robot with higher position and force resolutions to finish a smaller workpiece such as a plastic lens mold which conventional articulated-type industrial robots have not been able to deal with. The basic position/force control performance is shown, and present research progress and promising future works are introduced.