<title>Electroactive polymers (EAP) low-mass muscle actuators</title>

Abstract

Actuation devices are used for many space applications with an increasing need to reduce their size, mass, and power consumption as well as cut their cost. Existing transducing actuators, such as piezoceramics, induce limited displacement levels. Potentially, electroactive polymers (EAP) have the potential for low-mass, low-power, inexpensive miniature muscle actuators that are superior to the widely used actuators. Under electrical excitation, EAPs contract and thus form a basis for muscle actuators. Efforts are being made to develop EAP materials that provide large displacements, and two EAP categories were identified to produce actuation strain of more than 10%. These categories include: (1) ion-exchange membrane --platinum composite polymer (so-called ionomers); and (2) electrostatically driven polymers. A comparison between EAP and the widely used transducing actuators shows that, while lagging in force delivering capability, these materials are superior in mass, power consumption and displacement levels. This produces an enabling technology of a new class of devices. Several muscle configurations were constructed to demonstrate the capabilities of these EAP actuators. The emphasis of this manuscript is on ionomer actuators.