March 23, 2017

Solar-powered Skin Could Provide Sense of Touch to Prostheses

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Dahiya poses with a prosthetic hand covered in the solar-powered electronic skin. Photograph courtesy of the University of Glasgow.

Engineers from the University of Glasgow, Scotland, who previously developed an electronic skin covering for prosthetic hands made from graphene, have found a way to use some of graphene’s physical properties to harness energy from the sun to power the synthetic skin. The work could help create advanced prosthetic limbs that return the sense of touch to users and has implications for robots and wearable systems.

Graphene is a highly flexible form of graphite, which despite being just a single atom thick, is stronger than steel, electrically conductive, and transparent. It is graphene’s optical transparency, which allows about 98 percent of the light that strikes its surface to pass directly through it, that makes it ideal for gathering energy from the sun to generate power. A research paper, published March 22 in the journal Advanced Functional Materials, describes how Ravinder Dahiya, PhD, a reader in electronic and nanoscale engineering, and colleagues from his Bendable Electronics and Sensing Technologies (BEST) group have integrated power-generating photovoltaic cells into their electronic skin for the first time.

“My colleagues and I have already made significant steps in creating prosthetic prototypes which integrate synthetic skin and are capable of making very sensitive pressure measurements,” said Dahiya. “Those measurements mean the prosthetic hand is capable of performing challenging tasks like properly gripping soft materials, which other prosthetics can struggle with. We are also using innovative 3D-printing strategies to build more affordable sensitive prosthetic limbs….”

The new skin requires 20 nanowatts of power per square centimeter, which can be met even by the poorest-quality photovoltaic cells currently available. And although energy generated by the skin’s photovoltaic cells cannot currently be stored, the team is already looking into ways to divert unused energy into batteries, allowing the energy to be used when it is required.

Dahiya added, “The other next step for us is to further develop the power-generation technology which underpins this research and use it to power the motors which drive the prosthetic hand itself. This could allow the creation of an entirely energy-autonomous prosthetic limb.”

Editor’s note: This story was adapted from materials provided by the University of Glasgow.

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