A Soft End Effector Inspired by Cephalopod Suckers and Augmented by a Dielectric Elastomer Actuator

This article describes a soft suction cup end effector with squid-inspired suction generation and an octopus-inspired cup design that uses a dielectric elastomer actuator (DEA) to generate suction for adhesion. The fabrication process for the end effector is described in detail, and a mechanical model for generated pressure differential as a function of voltage is presented. When actuated, the DEA exerts an electrostatic stress on the walls of the end effector, resulting in pressure reduction in its water-filled cavity. The actuator is soft, flexible, and creates suction without a reliance on typical DEA elements such as rigid supporting structures and elastomer prestrain. It does not require net fluid flux out of the sucker, allowing faster attachment and easier release. It can be actuated underwater and has been validated with pull-off tests. The sucker generates a pressure differential of 3.63 +/- 0.07 kPa (+/- SD) when driven at 10.75 kV in water and should reach a 4.90 kPa pressure differential when energized at its theoretical failure point of 12.4 kV. Data normalized by the input voltage show that 90% of the maximum pressure differential can be achieved within 50 ms of voltage application. Weighing less than 30 g in air, this elastomer end effector is capable of pulling with a force of 8.34 +/- 0.10 N (+/- SD) and reversibly lifting 26.7 times its own mass underwater when actuated at 10.75 kV.