Planning of graspless manipulation by a multifingered robot hand

Graspless (or non-prehensile) manipulation is a method to manipulate objects without grasping. It includes pushing, tumbling and pivoting. Graspless manipulation is important as a complement of conventional pick-and-place for the dexterity of robots. In this paper, we propose a method of planning of general graspless manipulation by multifingered robot hands; the method can automatically generate various graspless operations by robot fingers including regrasping. In this method, a graph that represents feasible manipulation is constructed based on mechanical analysis and a manipulation plan is obtained by A* search of the graph. By considering whether each robot finger should be position- or force-controlled, we can obtain robust manipulation plans against external disturbances. We present some examples of planned graspless manipulation of a cuboid by two robot fingers; our planner successfully generates sliding, pushing and tumbling operations. We also show an experimental result of execution of planned graspless manipulation by a robot with a multifingered hand.