Bistable Antagonistic Dielectric Elastomer Actuators for Binary Robotics and Mechatronics

Binary systems can lead to simple and efficient robotic and mechatronic systems since such systems use a large number of simple bistable actuators to affect its state. Dielectric elastomer actuators (DEAs) are prime candidates for use in binary systems since they are simple, low cost, and lightweight. However, previously proposed bistable DEAs (flip-flop) have relatively low volumetric energy density that limits their use in practical devices. This paper investigates the potential of improving the energy density of bistable designs by employing DEAs in compact antagonistic configurations. To do so, two antagonistic configurations (linear and rotating) are designed and studied using an experimentally validated Bergstrom-Boyce viscoelastic material model. The proposed antagonistic configurations show up to similar to 10x higher volumetric energy densities than flip-flop designs. This represents a significant advantage for DEA reliability, since, based on volumetric energy density, antagonist actuators require the manufacturing of significantly less film layers than flip-flop designs. This study also reveals that, in the design of antagonistic DEAs, limiting the polymer film's actuation stretch minimizes viscoelastic losses and allows higher actuation speeds and power outputs for a given actuator stroke and size.