Reducing uncertainty of objects by robot pushing

A sensorless manipulation task eliminating geometrical uncertainty is proposed. It involves a two-fingered tool attached to a robot end effector. The object is assumed to be a convex polyhedron, although this assumption is later relaxed. Assuming that position and orientation are approximately known prior to operation, the initial position of the tool and the direction of movement are chosen. As the tool advances it strikes the object. If the trajectory is chosen properly, the fingers will contact the object with its corner between them. It is shown that such a configuration of contact points uniquely constrains the position of an object in all degrees of freedom