The broader impact/commercial potential of this project includes development of robust control algorithms for a robotic, foot-ankle prosthesis based on the winding filament hypothesis, a transformative new idea about how muscles contract. The winding filament hypothesis is uniquely able to account for properties of muscles that allow instantaneous and automatic adaptation of stiffness to unexpected changes in load. In the U.S. today, 1.6 -1.8 million persons live with loss of a limb. Despite the success of the latest technological improvements, significant challenges remain in development of robotic prostheses and other assistive devices. No devices available on the market today can reproduce normal walking movements under variable conditions (e.g., sand or other compliant substrates, stairs, steep ramps). These limitations affect quality of life by limiting participation in activities of daily life, including maintenance of physical fitness. Benefits of a robust powered prosthesis include increased versatility from level walking at a range of speeds, to stairs, ramps and varied terrain. The technology could also be extended to ankle orthoses for people whose mobility is limited by stroke, diabetes, or other conditions of disease and aging. In addition, development of bio-inspired control algorithms will enhance the scientific and technological understanding of muscle-like actuation.This Small Business Technology Transfer Research (STTR) Phase I project involves collaboration between a leading provider of robotic foot-ankle prostheses for persons with a lower limb amputation, and developers of the winding filament hypothesis, a transformative new idea about how muscles contract. The goal of the project is to demonstrate the technical and commercial feasibility of developing a robust control algorithm for a robotic prosthesis, based on the winding filament hypothesis. A powered, foot-ankle prosthesis will be modified to accommodate the bio-inspired control algorithms, the algorithms will be modified to account for prosthesis properties, and performance will be optimized for a broad range of terrains and conditions, including ramps, stairs and compliant surfaces. If the winding filament hypothesis algorithm can outperform the stock prosthesis controller in the range of conditions under which it emulates normal walking, this would provide proof-of-concept that a robust prosthesis controller is technically and commercially feasible. Robust control represents a disruptive market advance not only for prosthesis technology, but also for orthotic devices. A more versatile prosthesis would improve the quality of life for millions of Americans with limb loss.
