Toward broad optimal output bandwidth dielectric elastomer actuators

Dielectric elastomer actuators (DEAs) are one of the most promising soft actuation technologies owing to their relatively high power density and electromechanical efficiency enabled by a resonant actuation technique. However, existing DEA designs suffer from a very narrow optimal output bandwidth close to resonance and poor output control capability due to their fixed geometrical configurations. This condition greatly limits their applications in programmable actuation and broad-bandwidth applications. Accordingly, this work developed a novel resonance tunable DEA (RTDEA) design for broad-optimal-output actuation bandwidths that is enabled by an integration of a stiffness and voltage control strategy. This design features a broad resonant frequency adjustment from 84 to 126 Hz and independent tunings of its resonant amplitude and frequency. Parametric studies were conducted to illustrate the fundamental principles behind the resonance tuning strategy, and optimization was performed to maximize the tuning capability. Here, a resonance tuning control strategy is proposed to achieve accurate adjustments of the RTDEA’s resonance based on the stiffness and voltage control strategy. These resonance tunable soft actuators are envisioned to greatly expand DEAs’ applications in, for instance, soft robotic locomotion, human—robot communication, and active vibrational control with demands of broad actuation bandwidths and high output performance.