Aug 17, 2019 | Updated: 07:24 AM EDT

Knee Vibrations: A Source of Energy

Jul 19, 2019 08:09 AM EDT

Human Knee
(Photo : Pixabay)

Researchers from the University of Hong Kong have developed a device that can provide energy by walking. Their research was published in the journal Applied Physics Letters.

A wearer's knee is linked to an energy harvester which could generate 1. 6 microwatts of power while the wearer was walking. Small electronics like GPS devices and health monitoring equipment can be provided with enough power through this amount.

"Self-powered GPS devices will attract the attention of climbers and mountaineers," said author Wei-Hsin Liao, professor in the department of mechanical and automation engineering.

The energy harvester was a special smart macro fiber material that could generate energy through bending. This procedure allows the creation of a slider-crank mechanism that drives motors. The knee was chosen as the location to connect the device because the knee has a wide range of motion.

"These harvesters can harvest energy directly from large deformations," Liao said.

The device is capable of generating electricity because of the continuous motion of the walker. This implies the harvester can "capture biomechanical energy through the natural motion of the human knee," according to Liao.

The vibration from the device is the advantage of previous wearable energ harvesters. However, concerns related to efficiency is the concern with these devices.

"The frequency of human walking is quite slow, which significantly decreases the energy-harvesting capability," Liao said. Because the group's device uses a different method, it bypasses this limitation.

"The prototype weighs only 307 grams (0.68 pounds) and was tested on human subjects walking at speeds from 2 to 6.5 kilometers per hour (about 1 to 4 miles per hour). The researchers compared the wearers' breathing patterns with and without the device and determined that the energy required to walk was unchanged, meaning that the device is generating power at no cost to the human, " according to Tech Explore.

The researchers note the advantages of an efficient, wearable energyharvester and look towards future commercialization of the technology.

"Self-powered equipment can enable users to get rid of the inconvenient daily charge," Liao said. "This energy harvester would promote the development of self-powered wearable devices."

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