Dexterous Grippers: Putting Nonholonomy to Work for Fine Manipulation

In this paper, we describe the realization and control of robotic end-effectors that are designed to achieve high operational versatility with limited constructive complexity. The design of such endeffectors, which can be regarded either as low-complexity robot hands or as highly versatile robot grippers, is based on the intentional exploitation of nonholonomic effects that occur in rolling. While the potential usefulness of manipulation by rolling has been theoretically established in the literature, several problems in the practical implementation of the concept remained open. In particular, manipulation of parts of complex, and a priori unknown, shape is considered in this paper. Experimental low-complexity grippers that realize dexterous manipulation by rolling are also described. KEY WORDS—robotic hands, dexterous manipulation, shape reconstruction, motion planning, nonholonomic systems