Linear electroelastomer roll actuators

Dielectric elastomers are a class of electro-active polymers (EAPs), which can convert electrical energy to mechanical energy or vice versa. Elastic energy and power output of electroelastomers, also called dielectric elastomer artificial muscle, compare favorably with natural muscles. Variety of actuator configurations has been developed for variety of important applications including linear actuation, fluidic control and flat panel speakers. In particular, rolls are compact, have a potentially high electroelastomerto- structure weight ratio, and can be configured to actuate in several ways, including axial extension and bending. In this work a linear spring roll that can be extended in axial direction was fabricated. The amount of prestrain, type and physical properties of support structures as well as method of rolling and type of electrodes are the most important factors affecting the performance of the electroelastomer roll. Physical properties of the supporting such as material stiffness, can affect strain and energy output of the roll. A proper method should be used for rolling the electroelastomer to sustain the required prestrain and the uniformity of electrodes through out the roll. The electroelastomer roll was fabricated by rolling a special multilayered DE composite on a low friction support of proprietary design. A theoretical model was used to predict the thickness of each layer before and after actuation. Considering theoretical modelling, it was found that adding roll layers would increase force and strain output of the roll but the force increased more sharply than strain. To improve actuators performance two prestrech ratios λx, λy , were optimised. Finally it was found that uncured types of electrodes are not proper for multilayer actuators.

Keywords:

Dielectric elastomer actuator , Electroelastomer roll , artificial muscle