Most ankle-foot orthoses (AFOs) are stiff and uncomfortable, so a team of student researchers at Arizona State University (ASU)—Marielle Debeurre, Tiffany Hertzell, and Carly Thalman—has been working to create a dynamic, soft robotic AFO, or SR-AFO, that assists with gait rehabilitation by adjusting itself with each step. Their prototype uses 2 groups of soft inflatable actuators that actively adapt to the patient while they are using the device. One set of actuators braces the leg while the other assists with push-off during motion.
Thalman started the project during her first year as a systems engineering doctoral student in spring 2018. She began the AFO project by developing, modeling, and creating the fabric-based contracting actuator. The design was originally developed to help individuals with foot drop. Her fabric actuator design helped users achieve multiple degrees of freedom for ankle mobility. She went on to improve supportive actuators for lateral buckling prevention.
“Soft robotics are more innovative because they are lighter weight, comfortable for the user, inexpensive, and can still achieve the motions and force outputs of rigid robotics,” said Hertzell.
Future directions for this project involve investigating more advanced methods of gait detection to allow the SR-AFO to easily adapt to the user’s needs. Examples include assisting the ankle in various directions for increased support and encouraging fast, more fluid walking patterns. The idea is for the SR-AFO to easily adapt to any type of impairment with little adjustment and be comfortably worn during rehabilitation, like a piece of clothing.