A dielectric elastomer actuator thin membrane rotary motor

Abstract

We describe a low profile and lightweight membrane rotary motor based on the dielectric elastomer actuator (DEA). In this motor phased actuation of electroded sectors of the motor membrane imparts orbital motion to a central gear that meshes with the rotor. Two motors were fabricated: a three phase and four phase with three electroded sectors (120°/sector) and four sectors (90°/sector) respectively. Square segments of 3M VHB4905 tape were stretched equibiaxially to 16 times their original area and each was attached to a rigid circular frame. Electroded sectors were actuated with square wave voltages up to 2.5kV. Torque/power characteristics were measured. Contactless orbiter displacements, measured with the rotor removed, were compared with simulation data calculated using a finite element model. A measured specific power of approximately 8mW/g (based on the DEA membrane weight), on one motor compares well with another motor technology. When the mass of the frame was included a peak specific power of 0.022mW/g was calculated. We expect that motor performance can be substantially improved by using a multilayer DEA configuration, enabling the delivery of direct drive high torques at low speeds for a range of applications. The motor is inherently scalable, flexible, flat, silent in operation, amenable to deposition-based manufacturing approaches, and uses relatively inexpensive materials.