Departmental Papers (ESE)


We report on our progress in extending the behavioral repertoire of RHex, a compliant leg hexapod robot. We introduce two new controllers, one for climbing constant slope inclinations and one for achieving higher speeds via pronking, a gait that incorporates a, substantial aerial phase. In both cases, we make use of an underlying open-loop control strategy, combined with low bandwidth feedback to modulate its parameters. The inclination behavior arises from our initial alternating tripod walking controller and adjusts the angle offsets of individual leg motion profiles based on inertial sensing of the average surface slope. Similarly, the pronking controller makes use of a "virtual" leg touchdown sensing mechanism to adjust the frequency of the open-loop pronking, effectively synchronizing the controller with the natural oscillations of the mechanical system. Experimental results demonstrate good performance on slopes inclined up to /spl sim/250 and pronking up to speeds approaching 2 body lengths per second (/spl sim/1.0 m/s).

Document Type

Conference Paper

Subject Area

GRASP, Kodlab

Date of this Version

January 2001


Copyright 2001 IEEE. Reprinted from Proceedings of the IEEE International Conference on Robotics and Automation, Volume 4, 2001, pages 3650-3655.

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NOTE: At the time of publication, author Daniel Koditschek was affiliated with the University of Michigan. Currently, he is a faculty member in the Department of Electrical and Systems Engineering at the University of Pennsylvania.


Hexapod robot, legged locomotion, clock driven system, feedforward control, biomechanics, climbing, pronking



Date Posted: 02 June 2008

This document has been peer reviewed.