UT Dallas professor awarded $2.3 million NIH grant to continue prosthetics, orthotics research

Dr. Robert Gregg, an assistant professor of mechanical engineering and bioengineering who joined the Erik Jonsson School of Engineering and Computer Science this fall, is a recipient of a $2.3 million grant from the National Institutes of Health for research that will combine robot control theory and physical rehabilitation to revolutionize and improve prosthetic limbs and orthotic devices.

"According to the American Society of Mechanical Engineers report '2028 Vision for Mechanical Engineering,' mechanical engineers will need to collaborate with partners worldwide in order to apply innovative solutions and best practices to improve quality of life for all people," said Dr. Mario Rotea, head of the Department of Mechanical Engineering. "Dr. Gregg's research will contribute to this vision. His research combines mechanical systems, control theory, and embedded hardware and software to create next-generation prosthetics without the limitations of conventional solutions.

"His work is groundbreaking and of great value to society. This NIH award certifies his vision, and acknowledges the quality and potential applicability of his work to date."

The NIH Director's New Innovator Award supports the creation of wearable powered legs that coordinate with human movement and dynamically respond to the wearer's environment by measuring a single variable that represents the motion of the leg. These improved limbs could significantly increase the quality of life for millions of American amputees and sufferers of neuromuscular impairments, such as stroke survivors.

The award is given to researchers at an early stage in their career for work that is creative and has the potential for unusually high impact. Gregg is one of about 40 researchers throughout the country to receive the award.

"This award is not a just a recognition of the excellent research that Dr. Gregg is performing in prosthetic systems," said Dr. Robert Rennaker, head of the Department of Bioengineering, which grants graduate degrees in collaboration with UT Southwestern Medical Center and UT Arlington. "This award recognizes the disruptive nature of Dr. Gregg's intellect and his potential to change how we approach these types of challenges in biomedical engineering.

"Dr. Gregg, with the support of NIH, UT Dallas and UT Southwestern, has the potential to become a world-class researcher whose intellectual pursuits will radically change the future of prosthetic systems."

Much of the advancements in prosthetics and orthotics surround upgrades of the materials used for these devices, such as making them lighter and more flexible. These devices mimic human joints, but lack the ability to mimic the power generated from human muscles on able-bodied individuals. More recent advances include adding motors that generate force needed to respond to the wearer's environment, such as if someone is pushed; but they still lack the critical component of receiving input from the wearer or environment to adequately respond without falling.

Gregg proposes a new way to view and study the process of human walking: attaching sensors to mathematically meaningful locations on prostheses and orthotics that will allow the user to respond and control the device when their environment changes.

In addition, these devices would no longer require a team of physicians and physical rehabilitation specialists to spend significant amounts of time tuning and training each powered leg to the individual wearer.

"My vision is to have off-the-shelf robotic limbs that allow the owner to pick them up at a hospital or clinic, fit them on and walk off," he said. "Right now, we are nowhere close to that. It takes days of experimental tuning to get them to work properly, and then the movement is still less than ideal."

The New Innovator Award will cover testing of the new human phase variables on fully able-bodied people, as well as with individuals using prostheses and orthoses.

Later phases of the five-year award include testing this approach on leg function after spinal cord injury or stroke. Combined with other neuro-prostheses under development, this shift to human phase variable strategies might also lead to new technologies and therapies for individuals with peripheral neuropathy.

"This award will allow me to spend more time leading and practicing cutting-edge research," Gregg said. "Ultimately, it will also help improve the lives of millions of people affected by limited mobility."