Departmental Papers (ESE)

Document Type

Journal Article

Date of this Version

April 2000

Comments

Copyright 2000 IEEE. Reprinted from IEEE Transactions on Robotics and Automation, Volume 16, Issue 2, April 2000, pages 109-123.

This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of the University of Pennsylvania's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to pubs-permissions@ieee.org. By choosing to view this document, you agree to all provisions of the copyright laws protecting it.

NOTE: At the time of public, Daniel Koditschek was affiliated with the University of Michigan. Currently, he is a faculty member of the School of Engineering at the University of Pennsylvania.

Abstract

We report on our empirical studies of a new controller for a two-link brachiating robot. Motivated by the pendulum-like motion of an ape's brachiation, we encode this task as the output of a "target dynamical system." Numerical simulations indicate that the resulting controller solves a number of brachiation problems that we term the "ladder," "swing-up," and "rope" problems. Preliminary analysis provides some explanation for this success. The proposed controller is implemented on a physical system in our laboratory. The robot achieves behaviors including "swing locomotion" and "swing up" and is capable of continuous locomotion over several rungs of a ladder. We discuss a number of formal questions whose answers will be required to gain a full understanding of the strengths and weaknesses of this approach.

Keywords

brachiation, dynamically dexterous robotics, limit cycles, locomotion, swing map, symmetry, target dynamics, task encoding, underactuated system

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Date Posted: 13 March 2008

This document has been peer reviewed.