The dissipative dynamic performances of dielectric elastomer actuator with viscoelastic effects

Abstract

With large deformability and high energy density, Dielectric elastomers (DEs) deserve interest in soft robotics. Many challenges remain in the real-world applications, for the dynamic performance of dielectric elastomer actuator and their energy efficiency are affected by the dissipation mechanisms in the actuators. Concerning the viscoelasticity of DEs, we present a modeling approach to describe the dissipation mechanism to predict how the dissipative process affects the dynamic behavior. The validity and generalization of the model have been extensively verified under various excitation voltages (different peak voltages, frequencies, pre-stretching, and signal waveforms). For harmonic voltages at different frequencies (0.05, 0.1, 0.2, 0.5, 1 Hz), the root mean square error is less than 5.99%. The phase difference was adopted to quantify the viscoelastic hysteresis dissipative behavior of DEs. The results show that the viscoelastic hysteresis is sensitive to frequency and waveform. In addition, we found that the viscoelastic hysteresis of the DEs under harmonic excitation can be improved by inserting a small amount of saw-tooth excitation loads. This finding is particularly useful for the actuation of soft actuators and soft robots, which use alternating loads as the dominant excitation signal. For future applications, this model presents a method to describe the dissipative behaviors in dynamic actuation quantitatively and paves the way to high-performance actuation control and manipulations for soft robots.