A new concept for dielectric elastomer actuators: hydrostatic coupling

So-called dielectric elastomer (DE) actuators represent today one of the best performing technologies for electroactive polymer based actuation. This paper presents the concept for a new of class of DE actuators, with attractive potential capabilities for specific application needs. The proposed actuators use an incompressible fluid to mechanically couple an active elastic part with a passive elastic part. The active part works according to the DE actuation principle, while the passive part represents the end effector, in contact with the load. The fluid is used to transfer actuation hydrostatically from the active to the passive part and, then, to the load. This can provide specific advantages, including improved safety and less stringent design constraints for the architecture of the actuator, especially for its soft end effector. These might be of particular interest for many types of applications. Such a simple concept can be readily implemented according to different structures and intended functionalities of the resulting actuators. The paper describes some examples of actuators based on this concept and reports the preliminary performance of the first prototypes.