A compound-structure frame for improving the performance of a dielectric elastomer actuator

Actuators based on Dielectric Elastomer films have been rising as a promising technology in robotic and mechatronic applications. Their overall behavior is highly influenced by the geometry and structural properties of the frame that is coupled with the active film. In this paper, a compound-structure compliant frame is proposed with the aim of obtaining an actuator capable of providing a quasi-constant force over a certain range of motion. A “diamond” shaped frame, designed to support the pre-stretched active film, is coupled with a “delta” shaped element, designed to modify the overall actuator stiffness and improve its performance. Both the diamond and the delta element are fully compliant mechanisms whose main structural parameters are calculated using pseudo-rigid-body models and then verified through finite element analysis. Simulations show promising performance of the proposed actuator.