Electrostatic field induced coupling actuation mechanism for dielectric elastomer actuators

Abstract

Dielectric elastomer actuators (DEAs) exhibit many fascinating advantages, including high compliance, large actuation strain, fast response, high energy density and efficiency. These muscle-like properties make them suitable for robotic and mechatronic applications especially the actuation of soft robots. However, such actuators have experienced high rates of failure when operating at high voltage, which impedes their practical application to some extent. Here, we report an enhanced and reliable actuation mechanism which couples the electrostatic induction actuation and the electrostatic attraction or zipping mechanisms for DEAs. A circular DEA (E-DEA), a zipping DEA (EZ-DEA) and a bending DEA (E-DEMES) are redesigned and fabricated using this mechanism, which both survive the pull-in electromechanical instability and demonstrate higher operational voltages, larger attainable deformations, and longer actuation lifetime. The E-DEA achieves a large area strain up to 174% and can sustain 20-kV or even higher voltage, its equivalent dielectric strength is larger than 877 MV/m. The EZ-DEA achieves a larger out-of-plane deformation up to 8 mm compared to the traditional zipping DEAs. The E-DEMES is promoted 5 times in response speed and maximally about 87% in the transient blocking force. The improved E-DEMES also exhibits a great potential in faster actuation, larger actuation stroke and force for soft robots.