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A new way of harnessing the sun’s rays to power synthetic “skin” could help create advanced prosthetic limbs capable of returning the sense of touch to amputees.
According to a report in Energy Harvesting Journal, engineers from the University of Glasgow have already employed graphene in an electronic covering for prosthetic hands; now those engineers are putting graphene to work to collect energy.
Graphene is a highly flexible form of graphite that, despite being just one atom thick, is electrically conductive, stronger than steel and transparent. The optical transparency of graphene allows around 98 percent of the light that strikes its surface to pass directly through—ideal for gathering energy from the sun.
New research published in Advanced Functional Materials describes how Dr. Ravinder Dahiya of the University of Glasgow’s School of Engineering and colleagues from his Bendable Electronics and Sensing Technologies (BEST) group have integrated power-generating photovoltaic cells into their electronic skin. Dahiya says his team “have made steps in creating prosthetic prototypes [that] integrate synthetic skin and are capable of making very sensitive pressure measurements. Those measurements mean the prosthetic hand is capable of performing challenging tasks like properly gripping soft materials.”
Sensitive skin may have applications for robotics, as well. For example, if a robot working on a construction line can “feel” that a person has unexpectedly entered the area, the robot can stop moving, offsetting the possibility of an injury to the person.
With an eye toward accessibility, the team is using 3D printing to build affordable, sensitive prosthetics. Also, the new skin requires just 20 nanowatts of power per square centimeter, which is easily met by photovoltaic (PV) cells currently available on the market. The next steps are to divert into batteries unused energy generated by the PV cells. Dahiya also cites the need for technology to power the motors that drive the prosthetic hand.
The project’s mission is the creation of energy-autonomous prosthetic limb systems for affordable health care. To that aim, Dahiya and his colleagues have received funding from the Scottish Funding Council as well as commitments of time and ideas from the “Helping Hands” club composed of University of Glasgow students.