Hairy artificial skin gives robots a sense of touch

This patented smart skin is made from millions of self-powered sensors.
Written by Kelly McSweeney, Contributor on

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Hairy robots could be more sensitive to touch than humans. Researchers at the University of Texas at Arlington have patented a new artificial skin that could help robots collect information about their surroundings by using millions of tiny fibers.

The smart skin includes nanowire sensors made from zinc oxide (ZnO). They are much thinner than human hair (0.2 microns, while hair is around 40 microns), and when they brush against something, they can sense temperature changes and surface variations. These nanowires are covered in a protective coating that makes them resistant to chemicals, extreme temperatures, moisture, and shock, so they can be used in harsh environments. The nanowires and protective coating are bundled together into one sheet of pressure sensing "skin" that can be draped over a robot, so existing robots such as a fleet of industrial arms at a manufacturing plant could be retrofitted with a new sense of touch.

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While the image of hairy robots is endearing, the skin actually just looks like a sheet of plastic with patches of sensors. The "hairs" are so small that you can't feel them, and they can only be seen under a microscope.


Robots covered in this "hairy" smart skin could have more sensitive tactile feeling than humans. (Image: UTA)

The researchers describe their smart skin in a paper that published in IEEE Sensors Journal in 2015, and they have now received a patent for their technology. We asked the lead researcher Zeynep Çelik-Butler how this stands out from other smart skin technologies. In an email, she explained that it is self-powered, so there is no need to run wires or any signal to power it. The sensors are piezoelectric, which means they generate an electrical charge in response to mechanical stress.

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"The tactile pressure it senses powers it," she says. "It also fully conforms to the underlying surface it is attached to (robotic surface). There is no size limit for conformality." Compared to other smart skin, she adds, "The spatial resolution and the sensitivity is better."


Humans can't feel or see the "hair" because the nanorods are only 0.2 microns in diameter. (Image courtesy of the researchers.)

At the moment, the smart skin requires a"clean room" to achieve the ZnO nanowires without contamination. But Çelik-Butler explains that clean rooms are available in any semiconductor manufacturer, and portable clean rooms also exist.

In addition to robots, the smart skin could be applied to prosthetics in the future, to give them a sense of feeling. It could also be used to make "smart clothing" such as uniforms that can sense toxic chemicals or even identify a person based on a fingerprint.

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In a press release, Çelik-Butler said, "These sensors are highly sensitive and if they were brushed over a partial fingerprint, the technology could help identify who that person is. Imagine people being able to ascertain a person's identity with this hairy robot, as my students call it."

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