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Robots Have New Feel and Touch Sensor

Ravi Saraf believes robots, "with this method (...) it can sense down to about 10 microns."

As robots have so far lacked the capacity of accurately feeling objects, a new discovery made by Vivek Maheshwari and Ravi Saraf, of the University of Nebraska, will lead to a new dimension in robotic tactile feeling. The discovery will aid in robotic surgery, allowing for unparalleled sensitivity of the robotic arm.

The touch is sensed through a "sandwich" of alternate layers of gold and cadmium sulfide nanoparticles with a thin plastic sheet on top and glass below.

Based on the characteristics of the object felt, the image sensor beneath the glass recognizes the changes in electrical current and electroluminescence in the gold and cadmium sulfide nanoparticle layers.

Ravi Saraf

"Variation in stress distribution caused by the embossing on a 1c coin leads to significant change in local current density. These are conductive and semiconductive materials (gold and cadmium sulfide). When you press on the device with an applied voltage across the thickness, that results in larger current and electroluminescent light from the semiconducting particle. By focusing the emitted light intensity from the cadmium sulfide particles or the change in local current throughout the device, you know how much pressure you have applied and how it changes over the contact area.

Touch is a sensation they want in robotics because to tell the difference between a cube and a sphere, an ordinary robot takes forever to do it with vision because it has to look from all directions. With touch, it would 'feel' the sharp edges and say, 'Oh, this is a cube.' And then, of course, the big thing for the military is to maneuver in darkness. Similar to a blind person, (with this device) you can touch and find your way through."

"I am excited about this because I want to try to decipher cancer at the single-cell level," Saraf said. "Because in some cases, cancer tissues are harder than normal tissues, if you take a tissue sample, put it on a glass slide and press on it, you would be able to see a cluster of just a few (cancer) cells with this method because it can sense down to about 10 microns (10 millionths of a meter). Surgeons will be able to know if they have taken out all of the cancer. If they haven't, they'll know where to make the next cut."