The technology of touch: mini-motors enhance tactile world

Wearing a high-tech prosthetic hand, Eric Young grabbed hold of a Saltine.

Crunch.

The hand's rubbery, motorized fingers closed too quickly, and that's the way the cracker crumbled.

Then engineer Kelsey Muller flipped a switch, activating pressure-sensitive electronics so that when Young tried it again, the fingers would slow down at just the right moment.

Presto! Cracker intact.

"What we're doing is replicating the natural reflex," Muller said.

Her demonstration was one of more than a dozen Sunday afternoon at a Philadelphia symposium on an emerging technology called haptics.

Broadly, the field involves the use of electronics and miniature motors to create or enhance the sensation of touch. Those "vibrate" modes on a smartphone or a video-game controller? This is a much, much fancier version of that.

Researchers from around the world are at the DoubleTree by Hilton Hotel through Monday for the four-day event, affiliated with the New York-based Institute of Electrical and Electronics Engineers. Among the symposium organizers are University of Pennsylvania associate professor Katherine J. Kuchenbecker.

The possible applications of haptics are so varied that, in all likelihood, most of them have yet to be dreamed up.

In one corner of the hotel's third-floor ballroom, the cockpit of a driving simulator shuddered palpably as its operator steered his virtual vehicle into the "grass" alongside a road.

In another, researchers from Mexico's Autonomous University of Baja California administered soothing massages without actually touching anyone. They waved their fingers over a motion sensor, delivering pinpoint pressure to anyone game enough to lie down on a nearby electric massage pad.

Your beloved therapist moves across the country? No problem. All you need is the pad and an Internet connection.

It even works if the therapist is not available at the exact moment your aching joints need help, said Cristina Ramirez, a member of the project team.

"You can record it and play it back," she said.

The people behind the demos Sunday came both from academia and the private sector.

The pressure-sensitive modification of the prosthetic hand was developed by SynTouch L.L.C., a start-up company in Los Angeles.

They started with an off-the-shelf prosthetic hand, which is pretty cool even without the SynTouch addition. A person who has lost his hand can open and close the synthetic fingers by flexing his forearm, because the device measures electrical impulses in the arm muscles.

But picking up fragile items without crushing them? That's where the SynTouch modification comes in. The fingers are equipped with air-filled foam cells, so that when the fingers come into contact with an object, the device's internal electronics detect an increase in air pressure.

The system immediately instructs the fingers to slow down their grasping motion - recreating an action that most people perform without thinking.

Young, a doctoral engineering student at Penn and one of many who lined up to try the device, got the hang of it quickly.

"There's no training required," he said.

Across the room was William Provancher, from a start-up called Tactical Haptics, of Palo Alto, Calif. He presented a souped-up video-game controller that enabled users to feel as if they were picking up heavy objects.

One after another, participants strapped on a virtual-reality headset and grasped the controller, "lifting" boxes that existed only in the virtual world.

The controller's motors exert pressure on the wearer's fingers in various directions to create the sensations of lifting and pulling, among others.

Among those impressed was Domenico Prattichizzo, a senior researcher in advanced robotics at the Italian Institute of Technology in Genoa, Italy.

"It's really wonderful," he said. "You really feel something in your hands."

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