An artist's illustration of an artificial e-skin with nanowire active matrix circuitry covering a hand. It holds a fragile egg illustrating the functionality of the e-skin device for prosthetic and robotic applications.
Credit: Ali Javey and Kuniharu Takei
PARIS: 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 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.
Robots won’t break wine glasses
"Humans generally know how to hold a fragile egg without breaking it," said Ali Javey from 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."
‘E-skin’ made of sticky film
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 centimetres, 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.
Super-fast, like human skin
A different approach was taken by a team led by Zhenan Bao from 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 said.
"That means in real terms that we can feel the pressure instantaneously."
Touch the biggest obstacle
The achievements are "important milestones" in artificial intelligence, commented John Boland, a nanoscientist at Trinity College Dublin, Ireland, who hailed in particular the use of low-cost processing components.
In the search to substitute the human senses with electronics, good substitutes now exist for sight and sound, but lag for smell and taste.
Touch, though, is widely acknowledged to be the biggest obstacle. Even routine daily actions, such as brushing one's teeth, turning the pages of a newspaper or dressing a small child would easily defeat today's robots.
