Exploiting Bistability for High-Performance Dielectric Elastomer Resonators

Soft actuators with muscle-like motions have drawn increasing interests in areas such as bioinspired robotics and human–robot communications. Dielectric elastomers resonators (DERs), in particular, demonstrate outstanding output performance comparable to natural muscles by adopting a resonant actuation technique. However, their narrow resonant bandwidth results in poor adaptability and output consistency, thus greatly restrict their potential for real-world applications. To bridge this gap, this article presents a nonlinear mechanism coupled DER that exploits the inherent bistability and a unique subharmonic resonance to broaden the resonant bandwidth and to improve the output performance and energy efficiency. The proposed bistable DER demonstrates a broad resonant bandwidth that expands the resonant bandwidth of the DERs by over an order of magnitude. The inherent bistability also improves the power output by over two-fold and the energy efficiency by over four times in light viscous payload conditions. An intriguing nonlinear dynamic phenomenon, namely an isola, is uncovered both numerically and experimentally in this article, and is exploited to improve the energy efficiency and outputs of the DER at low applied electric field amplitudes. The outcomes of this article can offer guidelines for developing broadband and high-performing soft actuators.