Researchers at the University of Michigan have developed a knee exoskeleton designed to reduce fatigue and improve safety in lifting tasks. Built using commercially available knee braces and drone motors, the exoskeletons support the quadriceps muscles, allowing users to maintain proper lifting posture even when tired. This development aims to reduce workplace injuries, particularly in industries like construction and manufacturing where lifting is common. Unlike back braces or back exoskeletons, which are more intrusive and assume improper lifting techniques, these knee exoskeletons focus on strengthening the legs to promote safe squat lifting.
A study published in *Science Robotics* evaluated the device’s effectiveness. Ten participants—five women and five men—performed lifting and carrying tasks, both fresh and fatigued. Tasks involved lifting a 20-pound kettlebell from the ground and carrying it across various terrains, including stairs and inclines. The results showed that, when fatigued, participants using the exoskeleton maintained better posture and performed the tasks faster, with only a 1% reduction in speed compared to their pre-fatigue pace, versus a 44% slowdown without the device.
Robert Gregg, a professor of robotics at U-M and corresponding author of the study, explained that the exoskeleton’s motors and sensors provide a natural gait by allowing free knee movement. The software, which measures the user’s knee angle, leg orientation, and shoe force 150 times per second, enables seamless transitions between different tasks such as lifting and walking. This is a key improvement over many exoskeleton controllers, which often struggle to switch between tasks in real-time.
Participants in the study reported high satisfaction with the exoskeleton, particularly for lifting and walking on inclines, though they were less impressed with its performance on flat ground, where less quadriceps assistance is required.
The prototypes, currently costing around $4,000 per pair, could potentially be reduced to $2,000 if mass-produced. The research was funded by the National Institutes of Health, and the university is seeking partners to help bring the technology to market. Patent protection for the device has been applied for through U-M Innovation Partnerships.
