Pull-in instability of droplet amplified electrostatic actuators considering dielectric barrier discharge

Abstract

Liquid-amplified electrostatic actuators can generate greater forces than conventional ones which use air as the dielectric between two electrodes. Dielectric droplet amplified electrostatic actuators, a major type of liquid amplified electrostatic actuator, can be used to provide powerful, fast, energy-efficient, and lightweight actuations. However, the mechanical response of droplet amplified electrostatic actuator and the liquid amplification mechanism remain unexplored in a comprehensive way. Here we present a quasi-static model for droplet amplified electrostatic actuators considering dielectric barrier discharge and capillary force. The Galerkin method and the Newton method were used to numerically solve the model. A customized pull-in voltage measurement setup was established to verify the numerical results and the main influencing parameters were studied. The experimentally validated model can be used to accurately predict the quasi-static response and pull-in voltage of droplet amplified electrostatic actuators. This work highlights that the liquid amplification comes mainly from higher permittivity than air, dielectric barrier discharge elimination, and capillary force, due to the use of liquid dielectrics instead of air. The results in this work may provide useful insights into droplet amplified electrostatic actuator structural optimization, control, and application.