Electro-active polymers for actuation and sensing in space applications

Electro Active Polymers (EAPs) respond to an applied electrical potential with displacement. This permits their use for electrically-driven actuation mechanisms and in reverse as strain sensors. EAPs are currently the most promising class of materials for 'artificial muscles', as they are light-weight with high compliance, have high active strains and/or stresses depending on the kind of material (sometimes in excess of natural muscles), fast response (electronic type EAPs only), good controllability and low cost. This paper focuses on the potential of EAPs to provide solutions to integrating actuation and sensing functions required by future space systems. Performance indicators are covered, covering force levels, density, stiffness, displacement, power, and dynamic response. Their limitations are discussed in the context of environmental aspects, such as temperature, pressure, radiation, gravity, and in relation to robustness (degradation, fatigue). Dielectric elastomers are concluded to be the most promising class of EAP for application in a wide variety of space actuation tasks, and some of the possible applications of EAPs in space are Investigated. The paper concludes with a short case study on the use of a novel EAP device for a jumping mechanism in a Martian tumbleweed rover is presented as a novel example application.