Actuation Behavior of Hydraulically Amplified Self-Healing Electrostatic (HASEL) Actuator via Dimensional Analysis

Abstract

Electroactive polymer (EAP) actuators are an example of a novel soft material device that can be used for several applications including artificial muscles and lenses. The field of EAPs can be broken down into a few fields; however, the field that will be discussed in this study is that of Soft Electrohydraulic (SEH or EH) actuators. The device that will specifically be studied is the Hydraulically Amplified Self-Healing Electrostatic (HASEL) actuator. The design of the HASEL actuator is simple. There are two compliant films that house a dielectric liquid, and with the application of a voltage potential, there is an output displacement and force. However, the actuation mechanism is more complex, thus there is a need to understand theoretically and experimentally how the actuator works. This study analytically describes the electrode closure and the experimental testing of the actuators. Then, dimensional analysis techniques are used to determine what factors are contributing to the function of the actuator. For this study, eight dimensionless Π groups were found based on the derived analytical equation. These Π groups were determined based on the input voltage, density, viscosity, and elastic modulus of the materials; these were chosen because of their major contribution to the experimental data. The Π groups that are of particular importance are related to the characteristic length, which is directly related to the displacement of the fluid, the fluid velocity, the fluid pressure, and the dielectric constant. From this study, relationships between the output force, the electrostatic contributions, and other parameters were determined. All in all, this type of analysis can provide guidance on the development of high-performance HASEL actuators.

Multiresponse Liquid Metal Bionic Flexible Actuator

“…9 EAP actuation encounters challenges in regulating air volume, resulting in compromised motion stability. 10 The application scenarios of flexible actuators for fluid, chemical, SMA and EAP actuation types are limited by factors such as excessive energy consumption, challenging operating conditions, manual intervention requirements or intricate systems, hindering resource conservation, environmental friendliness and sustainable development. 11 Concurrently, nature offers a promising avenue for research by harnessing the potential of abundant light and humidity present in the environment.…”

“…The actuation of SMA exhibits slow response speed and varying thermodynamic states for different movements, which presents challenges in ensuring precise control progress . EAP actuation encounters challenges in regulating air volume, resulting in compromised motion stability . The application scenarios of flexible actuators for fluid, chemical, SMA and EAP actuation types are limited by factors such as excessive energy consumption, challenging operating conditions, manual intervention requirements or intricate systems, hindering resource conservation, environmental friendliness and sustainable development …”

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.…”