Biomimetic ratcheting motion of a soft, slender, sessile gel
- *Department of Applied Mathematics and Theoretical Physics, Cambridge University, Cambridge CB3 0WA, United Kingdom; and ‡Department of Chemical Engineering, Lehigh University, Bethlehem, PA 18015
-
Communicated by Joseph B. Keller, Stanford University, Stanford, CA, October 30, 2003 (received for review June 6, 2003)
Abstract
Inspired by the locomotion of terrestrial limbless animals, we study the motion of a lubricated rod of a hydrogel on a soft substrate. We show that it is possible to mimic observed biological gaits by vibrating the substrate and by using a variety of mechanisms to break longitudinal and lateral symmetry. Our simple theory and experiments provide a unified view of the creeping, undulating, and inchworming gaits observed in limbless locomotion on land, all of which originate as symmetry-breaking bifurcations of a simple base state associated with periodic longitudinal oscillations of a slender gel. These ideas are therefore also applicable to technological situations that involve moving small, soft solids on substrates.
Footnotes
-
↵ † To whom correspondence may be sent at the present address: Division of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138. E-mail: LM{at}deas.harvard.edu. §To whom correspondence may be addressed. E-mail: mkc4{at}lehigh.edu.
- Copyright © 2004, The National Academy of Sciences
