Paper: “On the Dynamic Similarity Between Bipeds and Quadrupeds: A Case Study on Bounding”
Authors: Zhenyu Gan, Ziyuan Jiao, and C. David Remy
Journal: IEEE Robotics and Automation Letters (RA-L), 2018
This research investigates the fundamental relationship between bipedal and quadrupedal locomotion by analyzing bounding gaits using passive dynamic models. The study introduces a quadrupedal model based on the spring-loaded inverted pendulum (SLIP) framework, but with dynamically swinging legs and a torso with variable inertia. By systematically varying model parameters and employing numerical continuation techniques, the authors identify all possible passive periodic motions that emerge from pronking and bounding behaviors.
The results show that bounding, commonly considered a quadrupedal gait, can be dynamically similar in both bipedal and quadrupedal systems when analyzed through the lens of passive mechanics. As the torso inertia changes, the quadrupedal model connects seamlessly to bipedal bounding behaviors, revealing direct correspondences between asymmetrical quadrupedal gaits and those found in bipeds. The study explains how different bounding gaits, including gathered suspension, extended suspension, and two-suspension bounding, emerge as a function of model parameters.
These findings provide evidence that the structure of possible gaits and their transitions are determined more by the underlying mechanics and energy than by the number of legs. The research offers a unified framework for understanding how morphology, inertia, and energy interact to shape gait selection. This has practical implications for robotics, suggesting that gait strategies developed for one morphology may be transferred to another when passive dynamics are considered. The work encourages a perspective where locomotion design is informed by physical principles rather than isolated to specific body plans.
Reference
@article{gan2018dynamic,
title={On the dynamic similarity between bipeds and quadrupeds: A case study on bounding},
author={Gan, Zhenyu and Jiao, Ziyuan and Remy, C. David},
journal={IEEE Robotics and Automation Letters},
volume={3},
number={4},
pages={3614–3621},
year={2018},
doi={10.1109/LRA.2018.2854923}
}