Hydraulically Enhanced Electrostatic Creeping Actuator Enabled by a Liquid-Metal Fluid Electrode

Area of Science:

• Robotics
• Materials Science
• Electrostatics

Background:

• Soft actuators are crucial for soft robotics.
• Existing actuators like dielectric elastomers and HASEL require high voltages, limiting human interaction.
• A need exists for low-voltage, high-performance soft actuators.

Purpose of the Study:

• To introduce a new class of soft actuators: hydraulically enhanced electrostatic creeping (HEEC) actuators.
• To demonstrate their low-voltage operation and high performance.
• To explore their potential in human-interactive soft robotics.

Main Methods:

• Fabrication of HEEC actuators using a polyvinyl chloride gel (PVCG) pouch filled with liquid metal (fluid cathode) between copper mesh anodes.
• Application of a low driving voltage (600 V) across the PVCG membrane.
• Coupling of hydraulic pressure and electrostatic creeping for actuation.

Main Results:

• HEEC actuators achieved 19% actuation strain and 200 mN output force at 600 V.
• Demonstrated superior performance compared to existing dielectric and hydraulic-amplified soft actuators.
• Enabled series assembly for versatile piston actuators with tunable strokes.

Conclusions:

• HEEC actuators offer a promising low-voltage solution for soft robotics.
• Their excellent deformation and performance make them suitable for human-interactive applications.
• Successful integration into a humanoid mask and robotic arm demonstrates practical potential.