The increased metabolic and biomechanical demands of ambulation limit community mobility in persons with lower limb disability due to neurological damage or advanced age. Robotic exoskeletons have the potential to assist these individuals to increase community mobility to improve quality of life. Current technology does not support dynamic movements, such as transitioning between different gaits and supporting a wide variety of walking speeds. This project proposes to meet this challenge by exploring an innovative myoelectric controller that brings together information across multiple muscles to assist the exoskeleton in a range of tasks for mobility. Of interest is how to extract information about the human user's intent, such as what speed the user wants to walk at or if they want to take a step up a stair. Recognizing intent will allow the device to give appropriate assistance over a wide range of activities. For this research project, the investigators will use a new type of robotic hip exoskeleton to augment the human hip during tasks such as walking at different speed, ramps and stairs. This project seeks to advance the state of the science in man-machine exoskeleton interfaces through new types of control techniques. This will help the team's long-term research goal of creating robotic assistive devices that benefit individuals with serious lower limb disabilities by improving mobility and, thus, overall independence. This NSF project will also include a significant outreach to the local Atlanta community. Local project partners will bring underserved minority students in the Atlanta area to Georgia Tech to participate in this educational program. These high school students will interact with the human assistive robotics in the lab and design, build, and program their own assistive robots through hands on education. This project will facilitate the training of an interdisciplinary group of students including graduate and undergraduate biomedical, electrical, and mechanical engineers, GT graduate students training to be clinical practitioners in prosthetics and orthotics, and physical therapists in training in Emory's DPT program. This interdisciplinary group of students will work together to fully integrate all aspects of the project and facilitate learning.
This research project will advance the knowledge of myoelectric (EMG) control for enabling humans to have dynamic movement assistance using lower limb robotic exoskeletons. Existing technologies of exoskeleton systems have limited high-level understanding of user intent, thus precluding adaptation to a proper range of daily tasks of living. Sensing modalities used in such systems do not provide sufficient information regarding key physiological parameters such as muscle activity. Conventional control algorithms relate a single modality of sensors to exoskeleton assistance and are thus incapable of fusing broader sets of varying sensor information. These technological gaps have impeded the translation of such systems beyond lab settings to clinical use where they can impact important health needs such as assistive rehabilitation. This proposal will address these gaps in assistive robotic technology by pursuing research organized in three key objectives: Objective 1) Determine the most effective strategy of providing exoskeleton hip assistance for reducing metabolic cost using a novel myoelectric controller. Objective 2) Compare the metabolic and biomechanical effects of a novel controller driven by myoelectric inputs vs a standard controller driven by kinematic inputs. Objective 3) Determine the contributions of high-level intent recognition using myoelectric information to improve control of a powered hip exoskeleton over simulated community terrain. Relatively simple mobility tasks like standing from a seated position or walking represent the primary outcome measures that determine independence in rehabilitation. Thus, the wearable exoskeleton system described in this grant proposal has the potential to make a measurable impact on enhancing the functional performance capabilities of individuals with lower limb deficits by increasing their quality of life, independence and well-being.
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.
