Nonprehensile Manipulation for Orienting Parts in the Plane

Abstract

The authors previously (1996) presented a model of nonprehensile manipulation, using two one-degree-of-freedom palms. Under the assumptions of low friction and quasistatic motion, we developed a planning method for part reorientation with our model, starting from a known initial state. Our method finds feasible paths through the space of equivalent state configurations of the object in the palms, without requiring that the palms maintain stable support of the object over the entire path. We have shown that such a device can reliably orient parts in the plane. In this paper we extend our method to the case of reorienting a part to a desired goal from an unknown initial state. In addition to the all sliding contacts case which the model is based upon, we look at extensions to rolling contacts. We include the results of tests with example plans.