1999 IEEE International Conference on Robotics and Automation

Toppling Manipulation

K. M. Lynch

Abstract

This paper describes a robotic manipulation primitive called toppling -- knocking a part over. We derive the mechanical conditions for toppling, express these as constraints on robot contact locations and motions, and describe an application of toppling to minimalist parts feeding of 3D objects on a conveyor with a 2 joint robot.
Available as postscript (624 K) and pdf (81 K)

See a video of toppling or the 2JOC home page.


Figure 1: The toppling transition directed graph showing the fence contact locations on the part that induce toppling to the next edge for different values of the fence friction coefficient and the conveyor friction coefficient. The fence contacts the part along a dark edge and maintains the contact point on the part as it rolls up and then topples over the pivot vertex.


Figure 2: This sequence of fixed-height pegs above a conveyor is capable of removing all uncertainty in the orientation of the triangle. The conveyor friction coefficient is 0.577 and the peg friction coefficient is 0.

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