Extreme-Hydrostatic-Pressure Resilient Dielectric Elastomer Actuator for Propeller Propulsion

Exploring high hydrostatic pressure environments such as deep sea presents significant challenges to robotic devices, for they often rely on strong yet heavy and costly protective structures to shield components from being crushed by the extreme pressure. To dismiss the need for bulky protection shells for actuation devices, we reported an extreme-hydrostatic-pressure resilient rotary dielectric elastomer actuator (DEA) for propulsion application in deep-sea pressure condition. DEAs are inherently resistant to damage caused by external pressure, due to their uniform and cavity-free structure. In this study, we analyzed the material properties of the DEA’s elastomer, evaluated the rotary actuator’s lifespan at up to 110 MPa high-pressure liquid conditions, and output performance under both ambient and 30 MPa (equivalent to 3,000 m underwater). Our results show that the rotary actuator maintained functionality at such hydrostatic pressure, with a lifespan exceeding 300,000 cycles and a high rotational output speed of 820 rpm. The rotary actuator was subsequently used to drive the robot with a propeller in a simulated deep-sea pressure fluidic environment, demonstrating our DEA’s performance as well as design simplicity for deep-sea applications without protection structures. While high hydrostatic pressure negatively impacted the actuator’s lifespan and slightly reduced its dynamic performance, our results confirmed that the DEA was a viable solution for deep-sea exploration, laying a solid foundation for the further development of DEA-powered devices for underwater missions.