Bidirectional rotational antagonistic shape memory alloy actuators for high-frequency artificial muscles

Area of Science:

• Materials Science
• Robotics Engineering
• Mechanical Engineering

Background:

• Shape memory alloys (SMA) offer high energy density for compact actuators.
• Current SMA actuators are limited to low frequencies (1-10 Hz) due to thermal activation.
• There is a need for faster SMA actuators in dynamic applications.

Purpose of the Study:

• To introduce a novel bidirectional rotational antagonistic (BIRAN) SMA actuator system.
• To achieve significantly higher actuation frequencies than previously reported for SMA wire actuators.
• To demonstrate the system's performance and potential for new applications.

Main Methods:

• Designed a novel actuator system architecture (BIRAN) using bundles of thin SMA wires.
• Developed specialized power electronics and control strategies.
• Conducted systematic experimental studies to evaluate system performance.
• Fabricated the actuator system and its components.

Main Results:

• Achieved a record actuation frequency of up to 200 Hz.
• Demonstrated repeated rotational movement with the BIRAN SMA actuator.
• The high frequency is attributed to the integrated mechanical design, electronics, and control.
• Showcased a bio-inspired robotic wing-flapping joint using the actuator.

Conclusions:

• The BIRAN SMA actuator system overcomes the dynamic limitations of traditional SMA actuators.
• The developed system sets a new frequency record for electrically activated SMA wire actuators.
• This technology expands the application possibilities for SMA actuators in high-frequency dynamic systems.