Driving Soft Robots with Low-Boiling Point Fluids

Abstract

Pneumatically-actuated soft robots are limited by the need to provide a source of pressure, typically DC motor powered pumps, compromising the softness of the overall system. This has motivated the investigation of alternative means of providing pressure, including mono-propellant decomposition, combustion of hydrocarbons in oxygen, and active composite foams. In this work, we propose the thermally driven evaporation of low-boiling point fluids as a facile method for providing pressure to soft robotic systems. We first discuss and test the thermodynamics of heating low-boiling point fluids. We then introduce two possible applications of low-boiling point fluids in soft robotics. First, we demonstrate a cheap and easily fabricated compliant heating element and show how this can be used to convert existing fluidic elastomer actuators to be driven by low-boiling point fluids. Secondly, we also demonstrate and characterise a soft-matter pump driven by low-boiling point fluids.