Locomotion is one of the most important human functions, serving survival, progress, and interaction. There are 2 million Americans living with an amputation and the majority of those amputations are of the lower limbs. Although current powered prostheses can accommodate walking, and in some cases running, basic functions like walking on various non-rigid or dynamic terrains are requirements that have yet to be met. The goal of this project is to develop and test a smart powered ankle-foot prosthesis that supports increased mobility for real-life activities. This smart service system will be able to identify and adapt to dynamic walking environment. Based on on-board sensing and the activations of the amputee's residual muscles, it will adapt its characteristics to allow for walking among different environments (e.g. concrete, asphalt, grass, gravel, loose sand) providing robust walking and balance to the amputee. The benefits of the acquired scientific and technological understanding from this project can extend beyond prostheses, to machines that interact with humans in cases of assistance and rehabilitation. The partnership's multidisciplinary expertise including engineering design, controls and human factors engineering, provides a unique environment for training of the students involved, and fosters an innovation culture in the next generation of researchers.
State-of-the-art lower limb prostheses provide reasonable solutions for walking over constant terrain; however, studies show that walking on variable and dynamic terrain may account for a very significant part of real-life functions. The ability to adapt performance at a level of intelligence seen in human walking is necessary to advance the current state-of-the art of lower limb prosthetic devices. This collaborative proposal aims to study the hierarchical processes contributing to the adaptive intelligence inherent in human walking, and to use that knowledge to develop a transformative state-of-the-art ankle-foot prosthesis. By analyzing the anticipatory and reactive mechanisms of the ankle dynamics when stepping on surfaces of different compliance, via the electromyographic signals of the involved lower limb muscles, this research is expected to enhance the scientific understanding of the control of ankle dynamics. Moreover, by incorporating these principles into the design of a hierarchical controller for a smart ankle-foot prosthesis, this program will enhance the technological understanding of advanced powered ankle-foot prosthesis that enables adaptation to the environment, currently not possible by the state-of-the-art prostheses.
