Chris Newmarker

August 1, 2014

2 Min Read
Why Have Five Fingers When You Can Have Seven?

Robotics not only has the potential to restore lost limbs to people--but also enhance the limbs we already have.

That is one of the intriguing takeaways from a recent innovation out of Massachusetts Institute of Technology. It's a robot worn around the wrist that works as though it was two extra fingers adjacent to the pinky and thumb. 

MIT engineering professor Harry Asada suspects the two-fingered robot might assist people with limited dexterity in performing routine household tasks, such as opening jars and lifting heavy objects.

A special control algorithm allows the robot to move in sync with the wearer's fingers to grasp objects of various shapes and sizes.

"This is a completely intuitive and natural way to move your robotic fingers," Asada says in an MIT news release. "You do not need to command the robot, but simply move your fingers naturally. Then the robotic fingers react and assist your fingers."

MIT Faye Wu supernumerary robotic fingers

MIT graduate student Faye Wu and the "supernumerary robotic fingers" device. Photo: Melanie Gonick/MIT

Asada and graduate student Faye Wu presented a paper the wrist robot last month at the Robotics: Science and Systems conference in Berkeley, CA.

The "supernumerary robotic fingers" include actuators linked together to exert forces as strong as those of human fingers. To figure out the algorithm needed to make them sync, Wu wore a glove with multiple position-recording sensors, and attached to her wrist via a light brace. She experimented holding items around the lab including a box of cookies, a soda bottle, and a football--and found that every grasp could be explained by a combination of two or three general patterns among all seven fingers.

The next step is to figure out how to get the robot fingers to automatically adjust force.

"Right now we're looking at posture, but it's not the whole story," Wu says. "There are other things that make a good, stable grasp. With an object that looks small but is heavy, or is slippery, the posture would be the same, but the force would be different, so how would it adapt to that? That's the next thing we'll look at."

The device could also be scaled down so that it is less bulky.

Refresh your medical device industry knowledge at MEDevice San Diego, September 10-11, 2014.

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Chris Newmarker is senior editor of MPMN and Qmed. Follow him on Twitter at @newmarker.

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