Counter-propagating waves enhance maneuverability and stability: A bio-inspired strategy for robotic ribbon-fin propulsion

Shahin Sefati, Izaak Neveln, Malcolm A. MacIver, Eric Fortune, Noah J. Cowan

Research output: Chapter in Book/Report/Conference proceedingConference contribution

23 Scopus citations

Abstract

Weakly electric knifefish, Eigenmannia, are highly maneuverable swimmers. The animals rely on a long, undulating ribbon fin to generate propulsive force. During closed-loop control of hovering and station keeping, knifefish partition their fin to produce two inward counter-propagating waves, enabling them to hover and rapidly change direction. In response to moving objects or changes in ambient flow speed, the fish can actively modulate the nodal point where the two waves meet. During hovering, this nodal point is somewhere in the middle, but it can be moved forward or backward changing the relative force generated by the front and back portions of the fin. Although this strategy for thrust generation may be energetically inefficient, we show here that it enables rapid switching of swimming direction and produces a linear drag-like force that confers passive stability. Robotic results and simple computational simulations reveal that the net force generated by counter-propagating waves changes linearly with respect to the nodal position. Another strategy for reversing swim direction would be to completely reverse the direction of a single traveling wave. We show why full wave reversal (and similar strategies) may be ineffective for low-speed swimming a regime where counter-propagating waves may simplify control.

Original languageEnglish (US)
Title of host publication2012 4th IEEE RAS and EMBS International Conference on Biomedical Robotics and Biomechatronics, BioRob 2012
Pages1620-1625
Number of pages6
DOIs
StatePublished - Oct 18 2012
Externally publishedYes
Event2012 4th IEEE RAS and EMBS International Conference on Biomedical Robotics and Biomechatronics, BioRob 2012 - Rome, Italy
Duration: Jun 24 2012Jun 27 2012

Publication series

NameProceedings of the IEEE RAS and EMBS International Conference on Biomedical Robotics and Biomechatronics
ISSN (Print)2155-1774

Other

Other2012 4th IEEE RAS and EMBS International Conference on Biomedical Robotics and Biomechatronics, BioRob 2012
Country/TerritoryItaly
CityRome
Period6/24/126/27/12

All Science Journal Classification (ASJC) codes

  • Artificial Intelligence
  • Biomedical Engineering
  • Mechanical Engineering

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