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Liquid crystal elastomer strips as soft crawlers

TitleLiquid crystal elastomer strips as soft crawlers
Publication TypeJournal Article
Year of Publication2015
AuthorsDeSimone, A, Gidoni, P, Noselli, G
JournalJournal of the Mechanics and Physics of Solids
Volume84
Pagination254 - 272
ISSN0022-5096
KeywordsCrawling motility; Directional surfaces; Frictional interactions; Liquid crystal elastomers; Soft biomimetic robots
Abstract

In this paper, we speculate on a possible application of Liquid Crystal Elastomers to the field of soft robotics. In particular, we study a concept for limbless locomotion that is amenable to miniaturisation. For this purpose, we formulate and solve the evolution equations for a strip of nematic elastomer, subject to directional frictional interactions with a flat solid substrate, and cyclically actuated by a spatially uniform, time-periodic stimulus (e.g., temperature change). The presence of frictional forces that are sensitive to the direction of sliding transforms reciprocal, ‘breathing-like’ deformations into directed forward motion. We derive formulas quantifying this motion in the case of distributed friction, by solving a differential inclusion for the displacement field. The simpler case of concentrated frictional interactions at the two ends of the strip is also solved, in order to provide a benchmark to compare the continuously distributed case with a finite-dimensional benchmark. We also provide explicit formulas for the axial force along the crawler body.

URLhttp://www.sciencedirect.com/science/article/pii/S0022509615300430
DOI10.1016/j.jmps.2015.07.017

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