Although volitional control of prosthetic arms has been studied intensively in recent years, similar technology has not yet been developed for lower limb prostheses, due in part to the lack of control capability in current passive prosthetic legs. Two emerging technologies, powered lower limb prostheses and neural-machine interfaces (NMI), have opened up new possibilities for allowing leg amputees to operate prostheses intuitively and to perform various activities in a natural way. It remains, however, to demonstrate the feasibility of volitional control for powered prosthetic legs. This is the PI's goal in the current project: to develop and implement a novel volitional controller that allows users with transfemoral amputations to operate a multifunctional, powered prosthetic leg intuitively and safely. To this end, she will systematically investigate and quantify the interaction effects between lower limb amputees and powered artificial legs. Intrinsic control (i.e., control based on intrinsic mechanical feedback) for a prototype powered transfemoral (TF) prosthesis will be developed with finite-state machine and impedance control mechanisms so that it can assist amputees in performing various activities in weight bearing and non-weight bearing situations. The design of the volitional control will be based on a multi-model engineering framework that integrates intent decoders with intrinsic prosthesis control so as to create feed-forward control in a powered TF prosthesis while ensuring amputee safety. Finally, a proof-of-concept prototype of a volitionally-controlled, powered TF prosthesis will be implemented and evaluated in real time on patients with TF amputations.

Broader Impacts: Project outcomes will significantly advance lower limb prostheses technology, which will in turn lead to quality of life improvements for the large and growing population of lower limb amputees. Similar technology should be applicable to control of powered orthotics, which would benefit patient populations with neuromotor deficits. The experimental data collected in the project will shed light on human motor control mechanisms, which should benefit diverse fields such as kinesiology and neuroscience. The new technologies developed in this research (including sensors, communication, algorithms, control, etc.) should help advance research across human-centered computing (including, for example, exoskeleton control and wearable sensors for health monitoring). Through integration of her research into comprehensive education and outreach programs, the PI will help educate the next generation of engineers and scientists, who will impact the future of science and technology.

National Science Foundation (NSF)
Division of Information and Intelligent Systems (IIS)
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Ephraim Glinert
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North Carolina State University Raleigh
United States
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