1992 IEEE International Conference on Robotics and Automation

The Mechanics of Fine Manipulation by Pushing

K. M. Lynch

Abstract

This paper presents a method for determining the possible instantaneous motions of a sliding object during multiple contact pushing. The approach consists of two components: a kinematic analysis considering kinematic motion constraints, and a force analysis considering force constraints on the motion. A new representation of the support friction of a sliding object is presented, and the results of the force analysis are independent of the exact support distribution of the object. The analysis results in a new manipulation primitive: stable rotational pushing. This primitive may be used for precise placement operations by pushing.
Available as postscript (300 K)

Figure 1: A pusher can make edge contact with any edge of the four-sided polygon shown. If the pusher rotates about a rotation center in in the Pn region, where the pusher is contacting edge n of the part, the part stays fixed to the pusher as it moves. (The friction coefficient here is 0.5, and the center of friction of the part is shown.) If the pusher rotates about a rotation center in a region labeled I, the part will not stay fixed to the pusher. The behavior for rotation centers in the unlabeled grey regions is unknown, as it depends on the precise support distribution of the part.
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