Shape Memory Alloy (SMA)-Enabled Actuators

About this technology

Overview

Researchers at NASA Glenn pioneered and matured SMAs to enable future aircraft with morphing airfoil surfaces and adaptive wings that fold to respond to different flight condition demands. SMAs are functional metals with unique properties that can go through solid-state phase transformations—stretched, bent, heated, cooled—and recover their original shape. NASA now has two novel mechanical actuators with SMA transmission elements to move parts with rotational angular twisting, delivering the same power as traditional actuators but in a lightweight, smaller footprint form factor. The new rotary actuator and ring drive actuator move in response to external stimuli, such as heating. The rotary actuator uses nested tubes of SMA to provide torque output or angular displacement; the ring drive actuator uses SMA tubes in a drive gear element to provide continual rotary output in either clockwise or counterclockwise directions. Despite the smaller footprint, the SMA tubes achieve higher power density and similar power output to larger actuators, enabling new designs based on compact actuators.