Scientists make ‘e-skin’ that can sense touch
Sept. 12: Biotech wizards have engineered electronic skin that can sense touch, in a major step towards next-generation robotics and prosthetic limbs. The lab-tested material responds to almost the same pressures as human skin and with the same speed, they reported in the British journal Nature Materials.
Important hurdles remain but the exploit is an advance towards replacing today’s clumsy robots and artificial arms with smarter, touch-sensitive upgrades, they believe.
“Humans generally know how to hold a fragile egg without breaking it,” said Ali Javey, an associate professor of computer sciences at the University of California at Berkeley, who led one of the research teams. “If we ever wanted a robot that could unload the dishes, for instance, we’d want to make sure it doesn’t break the wine glasses in the process. But we’d also want the robot to grip the stock pot without dropping it.”
The “e-skin” made by Javey’s team comprises a matrix of nanowires made of germanium and silicon rolled onto a sticky polyimide film. The team then laid nano-scale transistors on top, followed by a flexible, pressure-sensitive rubber. The prototype, measuring 49 square cm, can detect pressure ranging from 0 to 15 kilopascals, comparable to the force used for such daily activities as typing on a keyboard or holding an object.
A different approach was taken by a team led by Zhenan Bao, a Chinese-born associate professor at Stanford University in California who has gained a reputation as one of the top women chemists in the United States. Their approach was to use a rubber film that changes thickness due to pressure, and employs capacitors, integrated into the material, to measure the difference. It cannot be stretched, though.
“Our response time is comparable with human skin, it’s very, very fast, within milliseconds, or thousandths of a second,” Bao told AFP. “That means in real terms that we can feel the pressure instantaneously.”
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