Magnetorheological phase-change McKibben actuators for frequency-controlled actuation and high force output

Area of Science:

• Robotics
• Materials Science
• Actuation Technologies

Background:

• Soft robots face a performance-actuation trade-off: pneumatic systems are bulky, while smart materials lack force.
• Existing smart-material actuators struggle to meet the demands of high-performance soft robotics.

Purpose of the Study:

• To introduce a novel magnetorheological elastomer (MRE)-based phase-change McKibben actuator.
• To demonstrate wireless actuation via induction heating for soft robotic applications.

Main Methods:

• Utilized magnetorheological elastomers (MREs) with ferromagnetic particles for enhanced properties.
• Developed a multiphysics modeling framework integrating electromagnetic, fluid-pressurization, and structural analyses.
• Fabricated and tested prototypes operating at 127 kHz and 150 kHz induction frequencies.

Main Results:

• Achieved up to 70 N blocked force with a 23 g actuator mass.
• Demonstrated 48% higher force output and faster thermal response compared to hyperelastic actuators.
• Reduced actuation time by nearly 25% at 150 kHz, with heating times of 10-20 s.

Conclusions:

• The MRE-based phase-change actuator offers a promising solution for lightweight, high-performance soft robots.
• Wireless induction heating enables efficient and controllable actuation for advanced robotic systems.
• This technology addresses key limitations in current soft actuator designs, paving the way for more capable robots.