Characterization of gait energetics for electrically actuated quadrupeds

Despite the development of many quadrupedal robots and variety of possible running gaits, relatively little is known on the mechanisms that interplay between gait patterns and efficiency of quadrupedal machines. To gain insight on the energetics of robotic running, this work presents a study of the energetic trends across variations in gait and explores the mechanisms that are responsible for running efficiency for a quadrupedal robot. Motivated by the MIT Cheetah, the study uses a prototypical quadruped model, where DC motors are the main means of actuation, to extract principles for future control and design. This represents the first such study across gaits for robotic quadrupeds in the design paradigm of the MIT Cheetah. With the prototype model, we have found that it is energetically optimal to tend towards impulsive ground reaction forces on rigid terrain. Adding compliance at the contact interface lowers the cost of transport and increases the optimal duty ratio. In the optimal gaits, the total cost of transport is dominated by the cost of joule heating in the motors, and positive mechanical work only accounts for only 3-8% of the total cost. Analysis of trotting, pronking, bounding and galloping gaits reveals trotting to be the most energetically efficient gait across Froude numbers from 0.2 to 45. This trend represents a significant difference from animals, which transition to a gallop at a Froude number between 2 to 3.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Mechanical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2016

Author dc:creator

• Evans, Kathryn Louise, S.M. Massachusetts Institute of Technology

Advisor dc:contributor.advisor

• Sangbae Kim.

• Mechanical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/103464

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/103464