Table 1 Characteristics and applications of typical SMA actuator designs

Load characteristics

Linear variation, deterministic during repeated actuation

Nonlinear variation, deterministic during repeated actuation

Nonlinear variation, stochastic during repeated actuation

Typical loads

Weights, springs, torsion springs, and sliding friction

Flexible structures, soft structures, origami structures

Opposing SMA wires

System characteristics

Simple structure, intuitive mechanical transmission, easy to predict and control

Compact structure, capable of multi-angle, multi-DOF motion, high flexibility

Fast response speed, flexible actuation, high energy consumption

Application scope

Predictable motion paths, integration with traditional structures

Limited space, multi-DOF actuation

Applications requiring rapid reciprocation, multi-DOF actuation

Typical applications

Grippers^61,62,63, connection and release devices^65,66,67

Flexible rotary mechanisms^69,70, soft robotics^71,73,74, wearables^72,78

Bionic joints^82,83,84, 3D steerable needles⁸⁵