Wearable robot devices have been developed in the past by researchers at various universities and industry labs to help people in rehabilitation centers with walking or running, but small wearable devices could never seem to do both. Developing a robotic device to assist with walking and running can be a challenging task due to the different biomechanics of each gait. However, both gaits have the same extension of the hip joint, which begins whenever the foot touches the ground.
Researchers from Harvard’s Wyss Institute for Biologically Inspired Engineering and John A. Paulson School of Engineering and Applied Sciences (SEAS) and the University of Nebraska Omaha have developed an exosuit that helps the wearer with mobility while walking and running. The exosuit is made out of textile components worn at the waist and thighs, along with a mobile actuation system fixed onto the lower back which is controlled by an algorithm that detects the transition from walking to running. This is done by using sensors attached to the body that measure the wearer’s center of mass. The team’s report can be read in the Science journal.
The exosuit uses AI to determine whether the wearer is running or walking. It can be used to help improve mobility, especially for those undergoing rehabilitation from a stroke or other medical conditions. (Image Credit: Wyss Institute at Harvard University)
While running tests on a treadmill, the team found that metabolic costs of walking were reduced by 9.3 percent, and running by 4 percent, compared to when the device wasn’t in use.
The robotic hip exosuit is part of the Defense Advanced Research Projects Agency (DARPA)’s Warrior Web Program and is a result of research and optimization that took place over the past few years, with a focus on exosuit technology. A multi-joint exosuit already developed by the team in the past could help with the hip and ankle while the wearer is walking. Additionally, another version of the exosuit designed to improve gait rehabilitation for stroke victims is now available in the US and Europe, through a collaboration with ReWalk Robotics.
Current versions of the hip exosuit are designed to be lighter and easier to use compared to the multi-joint exosuit. A cable actuation system is put in place to assist the wearer. The cables add a tensile force between a waist belt and thigh wraps that supplies an extension torque at the hip joint, working in sync with the gluteal muscles. The exosuit weighs only 5kg with over 90% of the weight located near the user’s body of mass.
One of the toughest challenges the team had to overcome was that the exosuit needed to determine the difference between a running and walking gait while adjusting its actuation profiles according to the amount of assistance the wearer was provided with at the right time of the gait cycle.
Researchers hope the exosuit could assist wearers outside of rehabilitation centers, giving them the opportunity to run or walk more effectively.
“This breakthrough study coming out of the Wyss Institute’s Bioinspired Soft Robotics platform gives us a glimpse into a future where wearable robotic devices can improve the lives of the healthy, as well as serve those with injuries or in need of rehabilitation,” said Wyss Institute Founding Director Donald Ingber, M.D., Ph.D.
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