Design and experimental validation of a robust input shaper for eliminating vibration in dielectric elastomer actuators under varying applied voltage

Abstract

Dielectric elastomer actuators (DEAs) are an emerging type of soft actuator. When electrostatically actuated the DEA with a step signal, the inherent vibrations may limit their motion accuracy in practical applications. Moreover, increasing the applied voltage reduces the natural frequency of the dielectric elastomer structure, as the electrostatic stress decreases the tension in the DE device. This paper proposes a robust input shaper for a DEA system to eliminate vibration under various applied voltage. To extend the frequency control range of the shaper, an improved zero distribution method is proposed. The zeros are symmetrically distributed in the radial direction of the designed zero of a distributed zero-vibration (DZV) shaper. Simulations and experiments are performed to explain the robust control effects of the proposed design method. The step responses of the DEA are conducted at 2, 3 and 4 kV, the vibration attenuations of 27.66, 4.867 and 9.803 dB are achieved, respectively. Meanwhile, the overshoots are eliminated from the step responses. The designed method can pave the way to improve the control accuracy of soft material devices under varying operating conditions.