Farshad Khorrami, professor of electrical engineering, has spent two decades “[breathing] life into familiar materials with new robotics,” writes Robert Goodier on Scienceline.com, a publication of New York University’s Science, Health, and Environmental Reporting Program.
Mr. Goodier profiles Professor Khorrami’s current work at Polytechnic Institute of NYU where, as director of the Control/Robotics Research Laboratory, he is developing a robotic electric ray that “could be used to police harbors, seek mines or take samples of polluted water for laboratory studies.”
This exceprt explains how Professor Khorrami is trying to make the ray “stealthier” by using an alloy that will better mimic a ray’s smooth, muscle-like movement, and leverage its advantageously “lazy” qualities:
Khorrami admires electric rays, though he calls them lazy. The trait lends credibility to the robotic versions as underwater spies, he said. The robots can mimic real rays by lying on the sand while their sensors survey the area. Their laziness also manifests as methodical, conservative motion that Khorrami admires.
“With very little movement in that tail it can glide for a while. This is one of the beauties, that efficient action,” he said.
Recreating that action will require some engineering handiwork that pits the capabilities of machines against those of animals.
“I’m giving away some of the secret,” Khorrami said, looking away from the monitor where he had played the video of the ray. “Shape memory alloy.”
The alloy is a composite of nickel and titanium, called nitinol, that can “remember” a shape and return to it after it is bent. It simply requires heat. Khorrami gave a rough explanation of his plan: he will embed nitinol wires in the ray’s movable parts and activate them with a pulsing electric current. With each pulse the wires should make the parts twitch.
“The standard way to [make it move] would be to use off-the-shelf servos,” he said, referring to the devices that propel remote-controlled helicopters, for example. “We’re trying to develop our own [mechanism] to make it stealthier. When you move your arm you don’t hear much noise, do you? So the idea is, we’re trying to make it more like a muscle.”