Design and Control of Magnetic Shape Memory Alloy Actuators

Area of Science:

• Materials Science
• Mechanical Engineering
• Robotics

Background:

• Magnetic shape memory alloys (MSMAs) are advanced smart materials with significant strain capabilities and rapid dynamics.
• MSMAs enable shape change through martensite cell rearrangement under an external magnetic field.
• Existing MSMA actuator designs are reviewed to identify areas for improvement.

Purpose of the Study:

• To design, model, and control a novel actuator utilizing magnetic shape memory alloys.
• To develop and implement a hysteresis compensation strategy for improved actuator performance.
• To validate the actuator's performance through experimental testing and comparison with theoretical models.

Main Methods:

• Design and fabrication of a new MSMA actuator using 3 × 10 × 32 mm³ MSMA samples.
• Development of a dynamics model and derivation of the transfer function for the actuator.
• Application of the generalized Prandtl-Ishlinskii model for hysteresis compensation in the control system.
• Experimental validation using a custom-built test stand to measure step responses.

Main Results:

• The developed MSMA actuator demonstrated an operating range of up to 1 mm with high dynamics.
• The proposed inverse hysteresis model effectively compensated for non-linearities.
• Experimental results showed a positioning accuracy of ±2 µm for the compensated actuator.
• Theoretical analysis was compared with experimental actuator characteristics.

Conclusions:

• The novel MSMA actuator design, coupled with an inverse hysteresis control system, significantly enhances positioning accuracy.
• MSMAs are a viable material for high-performance actuators requiring precise control.
• The research validates the effectiveness of advanced modeling and control techniques for smart material actuators.