A physics-based modeling of a hydraulically amplified electrostatic actuator

Abstract

The focus of this study is to understand the physical phenomenon of the liquid-based electroactive polymer (EAP) actuator known as the Hydraulically Amplified Self-Healing Electrostatic (HASEL) actuator. Specifically, this study provides data in several areas, including the deformation of the film material, the dynamics of the dielectric liquid, and the electrical conditions within the actuator body. A two-dimensional model was developed in the finite element software, COMSOL Multiphysics, to create a generalized physics-based framework that describes the actuation mechanism. Much of the predictive data agreed well with the experimental data, such as the electrode pull-in occurring at ~4.5 kV and the displacement-voltage behavior. More importantly, the model also predicts basic fluid dynamic data, such as velocity (which reached a maximum of 0.7 m/s), the pressure of the fluid within the enclosed film, and the motion of the fluid, which have not been found in previous models. The model also predicts phenomenon seen in experimentation, such as fluid pockets under the electrodes and the interesting displacement-voltage behavior. Everything considered, the model connects the electrical, mechanical, and fluid systems, thus providing more detail about the dynamics of the actuator system and facilitating a shift in the current approach to modeling and designing these actuators.

Multimodal motion of soft origami tripod using electrohydraulic actuator

“…To solve the limitation, new approaches based on electrohydraulic actuators have been reported [17][18][19][20][21][22][23][24][25][26] . Electrohydraulic actuators have simultaneously used both electrostatic force and hydraulic pressure without an external pressure source.…”

Electrostatic-hydraulic coupled soft actuator for micropump application

“…Additionally, the use of viscoelastic acrylic elastomers in manufacturing DEAs constrains the displacement range. To address these issues, a hydraulically amplified self-healing electrostatic (HASEL) actuator was recently introduced, which utilizes an electrohydraulic mechanism for actuation [17][18][19]. A dielectric fluid with high dielectric strength in the HASEL actuator prevents a dielectric breakdown during actuation.…”