Design exploration of electro-pneumatic pumps (EPPs) to obtain high pressure and air flow rate improvement

The Electro-pneumatic Pump (EPP) is a lightweight, flexible electrostatic pump that uses a dielectric-liquidamplified zipping mechanism to control air volume and pressure and generate high air flow rate. In previous studies, the EPP, made of rectangular insulated electrodes, was capable of inflating/deflating pneumatic actuators and operating as a low power soft pump. This article explores a range of designs for the EPP electrodes to increase pressure generation, air transference and flow rate. As a result, the new EPP was able to generate a maximum pressure of 12.24 kPa, or a pressure difference of 11.25 kPa, corresponding to 481% improvement from the previous study. Additional liquid dielectric at 18% of the maximum available volume enabled the EPP to attain maximum EPP performance. The new design of the EPP was developed by combining two identical zipping regions and minimising the inactive region. Different actuator dimensions and actuation frequencies were investigated. The pump was capable of delivering a maximum flow rate of 238 ml/min at atmospheric pressure (48% improvement) at low power consumption of 0.4 Watt, and it could operate up to 4.47 kPa. It was found that the shape of the zipping region and the behaviour of the integrated compliant spring significantly influences the performance of the device. Lastly, approaches to further improve the EPP pump are discussed.