Researchers at Vanderbilt University have invented a nitrogen gas-powered thruster that is worn on the back that can correct falls as they start, restoring balance and averting potential injury.

Falls can lead to severe and fatal injuries, particularly for elderly people. According to the U.S. Centers for Disease Control and Prevention, millions of people fall each year, with one in five suffering serious injury.

Michael Goldfarb, a professor of mechanical engineering at Vanderbilt University, has first-hand experience dealing with this health risk. “As my parents grew older, both had experiences with fall risk that really limited their quality of life,” he said. “My father, in particular, had Parkinson’s disease.”

Goldfarb began thinking about new ways to correct occasional states of imbalance. Robotic exoskeletons can offer balance assistance, but have design challenges, such as having to coordinate a recovery response with the user. To avoid requiring a large frame or other structure (which would impede independence), he decided to focus on building a backpack-worn system that can apply forces directly to a person’s body using a thruster.

“This research challenge seemingly has not received much attention and therefore there were a lot of unknowns,” Goldfarb said. “Correcting a fall is a shared task between the person falling and the device helping to arrest the fall. What is the distribution of shared effort? How much force is appropriate to correct an impending fall? For how long is the force required? Can the magnitude of assistance required be provided by a compact cold-gas thruster?”

Goldfarb and fellow researchers Almaskhan Baimyshev and Michael Finn-Henry then set out to create a lightweight, cold-gas thruster (CGT) jetpack that senses when a fall has been initiated and can provide a restoring force to help the person recover his or her balance.