Piezoelectric “taxels” help robots to feel
Scientists at the Georgia Institute of Technology have created technology that allows robots to “feel” through a process which could foster new ways for humans to interact with electronic devices. The researchers used bundles of vertical zinc oxide nanowires to fabricate arrays of piezotronic transistors capable of converting mechanical motion directly into electronic controlling signals.
“The arrays include more than 8,000 functioning piezotronic transistors, each of which can independently produce an electronic controlling signal when placed under mechanical strain,” John Toon, from the Institute, explained.
“These touch-sensitive transistors – dubbed “taxels” – could provide significant improvements in resolution, sensitivity and active/adaptive operations compared to existing techniques for tactile sensing. Their sensitivity is comparable to that of a human fingertip.
“The vertically-aligned taxels operate with two-terminal transistors. Instead of a third gate terminal used by conventional transistors to control the flow of current passing through them, taxels control the current with a technique called “strain-gating.” Strain-gating based on the piezotronic effect uses the electrical charges generated at the Schottky contact interface by the piezoelectric effect when the nanowires are placed under strain by the application of mechanical force.”
Researchers cited possible uses for the technology as multidimensional signature recording, shape-adaptive sensing and active tactile sensing.
“Any mechanical motion, such as the movement of arms or the fingers of a robot, could be translated to control signals,” explained Zhong Lin Wang of the School of Materials Science and Engineering. “This could make artificial skin smarter and more like the human skin. It would allow the skin to feel activity on the surface.”
Future work will include producing the taxel arrays from single nanowires instead of bundles, and integrating the arrays onto CMOS silicon devices.