Abstract:
Pumps are widely used in nature and engineering to transport fluids, particles, and mixtures. Compared to those in engineering, most natural pumps are soft, highly efficient, and reliable. In this paper, we design a soft dielectric elastomer peristaltic pump (DEPP) inspired by the human heart. The DEPP is composed of two pump modules and each module consists of four layers of dielectric elastomer membrane and three layers of carbon grease as electrodes. The two pump modules are driven by two complementary signals with different waveforms including square, sine, sawtooth, and triangular waves. We build a measuring system including pressure and flow rate sensors to characterize the DEPP's performance. The experimental results reveal that the square wave voltage provides the highest flow rate and pressure difference compared to the other three waveforms. The mechanical resonance of DEPP is observed and the optimal frequency with square wave voltage is about 1.5 Hz, which falls in the range of the human heart rate. The optimal frequency decreases with the increase of electromechanical loads. In the experiment, compared with the existing dielectric elastomer pump, we obtain the highest average flow rate and the highest instant flow rate as 2.5 L/min and 3.2 L/min, respectively. The maximum pump volume per cycle for the DEPP is 0.09 L. It takes about 1 s for the DEPP to reach a new equilibrium state when the working frequency of the voltage is switched from 1 to 1.5 Hz. It is hoped that this study will guide the development of new artificial hearts and other soft industrial pumps.