Could robots develop a sense of touch? Apparently, they could. Researchers have designed a new "smart skin" that has the potential to give robots a more adaptive sense of touch, provide better security for handwritten signatures and offer new ways for humans to interact with electronic devices.
The "skin" is created from bundles of vertical zinc oxide nanowires that are fabricated into arrays of piezotronic transistors that are capable of converting mechanical motion directly into electronic controlling signals. The arrays themselves include more than 8,000 piezotronic transistors, each of which can independently produce an electronic controlling signal when placed under mechanical strain--otherwise known as being touched. These touch-sensitive transistors, which have been dubbed as "taxels", could provide significant improvements in comparison to existing techniques for tactile sensing. In fact, taxels are as sensitive as a human fingertip.
"Any mechanical motion, such as the movement of arms or the fingers of a robot, could be translated to control signals," said Zhong Lin Wang, a Regents' professor and Hightower Chair in the School of Materials Science and Engineering at the Georgia Institute of Technology, in a news release. "This could make artificial skin smarter and more like the human skin. It would allow the skin to feel activity on the surface."
Mimicking the sense of touch electronically has been challenging. Usually, it's managed by measuring changes in resistance prompted by mechanical touch. Yet the new devices manage it in a different way. They rely on tiny polarization charges formed when piezoelectric materials, such as zinc oxide, are moved or placed under strain. This allows the sensors to be far more sensitive than the usual ones.
In order to actually make the device, the researchers fabricated arrays of 92 by 92 transistors. They then used a chemical growth technique at around 85 degrees Celsius which allowed them to fabricate arrays of strain-gated vertical piezotronic transistors on substrates that were suitable for microelectronics applications.
So what can these devices be used for? Potentially, they could be utilized in multidimensional signature recording, or shape-adaptive sensing, which could be useful when developing prosthetic skin.
"This is a fundamentally new technology that allows us to control electronic devices directly using mechanical agitation," Wang said in a press release.
The researchers are planning to continue their work in producing the taxel arrays, including creating them from single nanowires instead of bundles.
