Issues in Nonprehensile Manipulation

Abstract

This paper outlines geometric and algorithmic issues common to various types of nonprehensile manipulation and gives some results for planar dynamic manipulation. 1 Overview Nonprehensile manipulation is manipulation without a form- or force-closure grasp. Examples include pushing, throwing, juggling, tapping, batting, and rolling (Mason [24]; Higuchi [11]; Buhler and Koditschek [6]; Erdmann [8]; Huang et al. [12]; Zumel and Erdmann [40]; Aiyama et al. [1]; Trinkle and Zeng [37]). In each of these examples, the robot takes advantage of the natural task dynamics to help control the motion of the part. Nonprehensile manipulation occupies the majority of the manipulation spectrum, comprising everything between situations where the robot exerts complete control to situations where the natural dynamics exert complete control. During a baseball throw, the ball is at first held firmly in the hand, then is allowed to roll off the fingers, and finally follows a free-flight trajectory determined by gravity and air resistance. The nonprehensile manipulation problem is to arrange the rolling motion on the fingers such that the release state will allow the ball to reach the goal state