Large actuation in an electromechanical actuator using gel, elastomer, and oil

Dielectric elastomer actuators have attracted much attention in the application of soft robotics. In this work, we present a new design of electromechanical actuator using gel, dielectric elastomer and oil. Compared to the traditional dielectric elastomer actuator, we replace the electrodes with conductive gel and replace the dielectric elastomer with a combination of oil and elastomer. In our new design, the electrostatic force works against the bending deformation of the gel electrodes. When the applied voltage reaches a critical value, the two gel electrodes pull in and large actuation can be achieved. We present a theoretical analysis by modeling the actuator as a thin membrane subject to the electrostatic pressure and mechanical tension. We fabricate the actuator and demonstrate a large voltage induced actuation strain by pull-in instability. The experimental results verified the theoretical predictions.