Powered ankle prostheses have been proven to improve the walking economy of transtibial amputees although these powered systems are usually much heavier in weight than conventional prostheses. All commercial powered ankle prostheses that are currently available can only perform one-degree-of-freedom motion in a limited range. However, the human ankle can perform both frontal and sagittal plane motions. Studies have shown that the frontal plane motion during ambulation is associated with balancing. As more advanced neural interfaces have become available for amputees, it is possible to fully recover ankle function by combining neural signals and a robotic ankle. Accordingly, there is a need for a powered ankle prosthesis that can have active control on not only plantarflexion and dorsiflexion but also eversion and inversion.
The prosthesis in this project is a second-iteration design based on its predecessor. The new design features a larger joint range of motion, a more robust and efficient transmission, and a more powerful battery module. At present, a system with such capabilities only exists as tethered.