Sticky space snakes: hyper-redundant DEA robots with electro-adhesive feet

Abstract

Soft robots with many degrees of freedom, modelled after snakes or tentacles, can locomote through a combination of controlled friction and phased multi-segment deformation. Using different periodic motions (gaits) snakes (and snake-like robots) are able to cross open space, climb narrow passages, side-wind across granular substrates, and more. Unlike their biological counterparts, snake-like robots should be able to adapt easily to space flight by utilising controllable friction elements in the form of electro-adhesive pads to selectively attach to and detach from surfaces and objects. They could operate on the interior and exterior of satellites to perform maintenance and repair, or even explore the surfaces of small astronomical bodies which do not produce enough gravity to allow for traditional wheeled rovers. Dielectric elastomer actuators (DEAs) are an ideal candidate for the driving system of such a robot, and have already demonstrated the ability to form multi-degree of freedom actuators of varying design. They are lightweight, use minimal current to maintain a given position, have high energy density, and are capable of self-sensing their strain, reducing the need for external monitoring. We present here the design and analysis of a lightweight DEA snake-like robot incorporating electro-adhesive elements for operating in zero-gravity environments, including different gait waveforms for enhanced performance and finite element analysis for design optimisation. We conclude with discussion of future improvements, such as the incorporation of dielectric elastomer switches for greater autonomy.