CUHK Researchers Design Energy-Harvesting Knee Brace

Researchers from the Chinese University of Hong Kong have designed a knee brace that harvests energy while the joint is in motion. Users can walk, run, and exercise while the brace generates 1.6 microwatts power, all without any increase in effort. The team describes their new brace in a recently released paper entitled, “Macro fiber composite-based energy harvester for human knee,” which uses a smart macro fiber material and a slider-crank mechanism to generate energy.

The energy-generating brace features a rod joined to a band the wearer’s thigh that moves back and forth through a slide attached to the user’s calf with another band. Both the rod and slide can pivot, so when the users move their knee, the system can slide back and forth without obstruction. A carbon fiber strip outfitted with a ‘smart’ macro fiber composite material (MFC) is affixed to both the rod and slider, which generates an electric current when it bends during motion of the knee.

Although the brace only generates 1.6 microwatts of energy at walking speeds of 1 to 4 mph, it’s enough to power health-monitoring devices or a GPS unit. The researchers tested the brace using several volunteers and found their breathing patterns hadn’t changed while walking on a treadmill, meaning they didn’t have to expend additional energy while wearing the device, which weighs just 0.7-pounds. The hope is that the technology could be utilized by mountaineers, hikers, and other outdoor enthusiasts who need to keep their portable devices charged in remote locations.

Sandwich to raw energy at its finest.