Shape Memory Alloy Rotary Actuators for Aerospace: Part 2 Integration and Application

Shape memory alloys (SMA) provide a compact, robust, light-weight and scalable rotary actuation technology with precise control for many aerospace applications that require high torque output. With their high energy density, SMA rotary actuators can often be integrated directly into or near the hinge line reducing the need for complex kinematics (e.g., linkages and gears) typically required to transfer the work output from the actuator to the effector system. Despite these benefits, earlier attempts to integrate SMA actuators into aerospace applications were limited by an incomplete understanding of the materials, a lack of engineering design tools, and insufficient experience at designing to meet rigorous requirements. In the last two decades, significant strides were made in addressing key issues limiting the commercialization of SMA actuation technology. These continuous advances include the publication of standard specifications and test methods for SMA actuation, the development and implementation of design and optimization tools, improved alloys and supply chain maturation. With these recent advancements, high technology readiness level demonstrations and some production use of scalable SMA rotary actuation technology was demonstrated across several aeronautical platforms including wind tunnel to full-scale flight test of reconfigurable vortex generators, actuated wind tunnel models, ram air door actuators, adaptive trailing edges, power door opening systems and spanwise adaptive wings. The required torque output for these applications and their SMA torque tube elements ranged from 100 N mm to 2200 N m. This presentation will highlight application development from requirements through full scale testing including flight tests on aerospace platforms.