PFI-RP: Developing Market-Ready Affordable Robotic Lower-Limb Prostheses through Unified Joint Actuator Design and AI-Enhanced Multi-Modal Interactive Control

The broader impact/commercial potential of this Partnerships for Innovation – Research Partnerships (PFI-RP) project is the availability of a highly affordable powered lower-limb prosthesis that provides versatile (multi-modal) operation in amputee users’ daily life. Currently there are approximately 2 million people living with limb losses in the U.S., and half of them are lower-limb amputees. Currently available prosthetic devices are mostly passive, unable to generate joint power in locomotion. As such, the passive prosthesis users typically experience substantial difficulty and discomfort in daily life, for example, being unable to climb stairs, walking in an obviously asymmetric way, and expending more energy in walking. There are two powered prosthetic devices for lower-limb amputees, but limited success has been reported due to issues such as high cost and difficulties in control and user intent recognition. The research and development efforts in the proposed project aim at overcoming these problems by creating an innovative lower-limb prosthesis that combines low cost, light weight, high reliability, and task versatility. With this innovative prosthetic device, the PFI team anticipates accelerating the lower-limb amputees’ acceptance of advanced robotic prostheses and significantly improve their mobility and quality of life in daily living. The proposed project will explore multiple innovative technologies towards the development of the new powered lower-limb prosthesis. Firstly, it includes the development of a novel Common-Core-Components Knee-Ankle Prosthesis (C3KAP) design technology providing simple, low-cost, and highly reliable prosthetic joints that can be easily configured as prosthetic knee or ankle, supplemented by a novel variable stiffness force-moment load cell providing sensitive and reliable load measurement for prosthesis control. Secondly, it aims to develop a new bi-modal prosthesis motion control technology that provides natural leg swing motion, interactive stance-phase control, as well as simple and standardizable controller tuning for individual users. Finally, the PFI team will create an advanced AI-based intent recognizer to recognize the prosthesis users’ locomotive mode and desired mode transition, enabling amputees to enjoy the freedom of true multi-modal locomotion (walking and stair ascent/descent), significantly improved mobility and quality of life. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.