Soft pump producing a rapid flow using shell buckling

Abstract

Soft pneumatic pumps have played a significant role in improving the portability and adaptability of soft robots. However, they also had difficulties actuating stiff pneumatic devices and inducing rapid motion. Here, we introduce a soft pump, overcoming these limitations by using the snap-through instability and finely controlling the performance using an electro-active polymer. The soft pump consists of a spherical shell and two open cylindrical channels attached to opposite sides of the shell. Electrodes are attached to the surface of the pump to induce electrical responsiveness. The soft pump is axially stretched at a constant velocity. As the total length of the pump reaches a critical value, the spherical shell buckles and generates rapid outflow. In addition, the applied voltage on the electro-active soft pump programs the maximum flow rate and the mechanical power by changing effective geometric parameters and material properties. We conduct the finite element method (FEM) and experiments to verify the actuating behavior and the reprogrammability of the soft pump. FEM is used to obtain the maximum volume of the exposure air for different geometric parameters, material properties, and applied voltages. Experiments are used to evaluate the performance of the soft pump running a pneumatic device controlling the applied voltage. This work presents the potential of the novel soft pump as an advanced actuator since the single pump can drive various pneumatic devices by reprogramming the maximum flow rate.