Bird-Inspired Tendon Coupling Improves Paddling Efficiency by Shortening Phase Transition Times

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Bibliographic Details
Title: Bird-Inspired Tendon Coupling Improves Paddling Efficiency by Shortening Phase Transition Times
Authors: Lin, Jianfeng, Zhao, Guo, Badri-Spröwitz, Alexander
Source: 2025 IEEE International Conference on Robotics and Automation (ICRA). :15936-15942
Publication Status: Preprint
Publisher Information: IEEE, 2025.
Publication Year: 2025
Subject Terms: FOS: Computer and information sciences, Computer Science - Robotics, Biological Physics (physics.bio-ph), FOS: Physical sciences, Physics - Biological Physics, Robotics (cs.RO)
Description: Drag-based swimming with rowing appendages, fins, and webbed feet is a widely adapted locomotion form in aquatic animals. To develop effective underwater and swimming vehicles, a wide range of bioinspired drag-based paddles have been proposed, often faced with a trade-off between propulsive efficiency and versatility. Webbed feet provide an effective propulsive force in the power phase, are light weight and robust, and can even be partially folded away in the recovery phase. However, during the transition between recovery and power phase, much time is lost folding and unfolding, leading to drag and reducing efficiency. In this work, we took inspiration from the coupling tendons of aquatic birds and utilized tendon coupling mechanisms to shorten the transition time between recovery and power phase. Results from our hardware experiments show that the proposed mechanisms improve propulsive efficiency by 2.0 and 2.4 times compared to a design without extensor tendons or based on passive paddle, respectively. We further report that distal leg joint clutching, which has been shown to improve efficiency in terrestrial walking, did not play an major role in swimming locomotion. In sum, we describe a new principle for an efficient, drag-based leg and paddle design, with potential relevance for the swimming mechanics in aquatic birds.
Submitted to ICRA 2025; Supplementary Video: https://youtu.be/lUU3LwMy6AM
Document Type: Article
Conference object
DOI: 10.1109/icra55743.2025.11128691
DOI: 10.48550/arxiv.2409.14707
Access URL: http://arxiv.org/abs/2409.14707
Rights: STM Policy #29
CC BY
Accession Number: edsair.doi.dedup.....53f347c166143ddc34c3949c6b3682a9
Database: OpenAIRE
Description
Abstract:Drag-based swimming with rowing appendages, fins, and webbed feet is a widely adapted locomotion form in aquatic animals. To develop effective underwater and swimming vehicles, a wide range of bioinspired drag-based paddles have been proposed, often faced with a trade-off between propulsive efficiency and versatility. Webbed feet provide an effective propulsive force in the power phase, are light weight and robust, and can even be partially folded away in the recovery phase. However, during the transition between recovery and power phase, much time is lost folding and unfolding, leading to drag and reducing efficiency. In this work, we took inspiration from the coupling tendons of aquatic birds and utilized tendon coupling mechanisms to shorten the transition time between recovery and power phase. Results from our hardware experiments show that the proposed mechanisms improve propulsive efficiency by 2.0 and 2.4 times compared to a design without extensor tendons or based on passive paddle, respectively. We further report that distal leg joint clutching, which has been shown to improve efficiency in terrestrial walking, did not play an major role in swimming locomotion. In sum, we describe a new principle for an efficient, drag-based leg and paddle design, with potential relevance for the swimming mechanics in aquatic birds.<br />Submitted to ICRA 2025; Supplementary Video: https://youtu.be/lUU3LwMy6AM
DOI:10.1109/icra55743.2025.11128691