An Overview of Shape Memory Alloy-Coupled Actuators and Robots

Area of Science:

• Materials Science and Engineering
• Robotics and Mechatronics
• Mechanical Engineering

Background:

• One-dimensional deformation of shape memory alloys (SMAs) can create complex three-dimensional deformations in functional structures.
• SMA elements are integrated into structures as rigid joints, semi-rigid hinges, or attached/embedded components in soft structures.
• These diverse implementations enable the creation of robots exhibiting both rigid and soft motions.

Purpose of the Study:

• To classify and review different types of functional structures utilizing SMA elements for 3D deformations.
• To present research efforts, strengths, and weaknesses of SMA-based actuators and robots for each structure type.
• To develop a model comparing the performance and design parameter selection for SMA wires versus SMA springs in polymeric matrix actuators.

Main Methods:

• Literature review and categorization of SMA-based functional structures and robotic applications.
• Analysis of strengths and weaknesses for different structural classifications and SMA implementation methods.
• Development of a comparative model to evaluate SMA wires and springs within polymeric matrix actuators.

Main Results:

• Identified four main categories of SMA-implemented structures: rigid joints, semi-rigid hinges, externally attached, and embedded elements.
• Detailed the diverse properties, requirements, and applications of these structures in robotic systems.
• The developed model provides insights into the performance trade-offs between SMA wires and springs for specific actuator designs.

Conclusions:

• SMA elements offer versatile solutions for creating 3D deformations in functional structures, leading to novel robotic designs.
• The choice between SMA wires and springs depends significantly on the specific application, structural type, and desired actuator performance.
• Further research can leverage this classification and modeling approach to optimize SMA-based actuator and robot development.