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Prosthetic turns drummer into 3-armed ‘cyborg’

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This robotic drumming prosthesis has motors that power two drumsticks. One is controlled by muscle sensors. The other is autonomous. (Credit: Georgia Tech)

A new robotic drumming prosthesis has two drumsticks—the musician’s arm and muscle sensors control one, and the other “listens” to the music and improvises.

A new robot can be attached to amputees, allowing its technology to be embedded into humans. The robotic drumming prosthesis has motors that power two drumsticks. The first stick is controlled both physically by the musician’s arm and electronically using electromyography (EMG) muscle sensors. The other stick “listens” to the music being played and improvises.

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“The second drumstick has a mind of its own,” says Professor Gil Weinberg, founding director of the Georgia Tech Center for Music Technology. “The drummer essentially becomes a cyborg. It’s interesting to see him playing and improvising with part of his arm that he doesn’t totally control.”

The prosthesis was created for Jason Barnes, a drummer who was electrocuted two years ago and lost his right arm below the elbow. The Atlanta Institute of Music and Media student built his own prosthetic device shortly after the accident. It wasn’t very flexible. He could bang the drums by moving his elbow up and down, but couldn’t control the speed or bounce of the stick without a wrist or fingers.

That’s when Weinberg stepped in to create a single-stick device with sensors that respond to Barnes’ bicep muscles.

“Now I can flex and send signals to a computer that tightens or loosens the stick and controls the rebound,” says Barnes.

The extra stick

Weinberg, who has already built a robotic percussionist and marimba player that use computer algorithms to improvise with human musicians, took the prosthesis a step further. He added the second stick and gave it a “musical brain.”

“Jason can pull the robotic stick away from the drum when he wants to be fully in control,” says Weinberg. “Or he can allow it to play on its own and be surprised and inspired by his own arm responding to his drumming.”

Regardless of how he uses the extra stick, the new prosthetic has already given Barnes capabilities he hasn’t had since before the amputation.

“Music is very time sensitive. You can hear the difference between two strokes, even if they are a few milliseconds apart,” says Weinberg. “If we are able to use machine learning from Jason’s muscles (and in future steps, from his brain activity) to determine when he intends to drum and have the stick hit at that moment, both arms can be synchronized.”

Astronauts and surgeons

Weinberg says such robotic synchronization technology could potentially be used in the future by fully abled humans to control an embedded, mechanical third arm during time-sensitive operations. For example, Weinberg’s anticipation algorithms could be used to help astronauts or surgeons perform complex, physical tasks in synchronization with robotic devices.

For Barnes, it’s all about the music. Because an embedded chip can control the speed of the drumsticks, the prosthesis can be programmed to play two sticks at a different rhythm. It can also move the sticks faster than humanly possible.

“I’ll bet a lot of metal drummers might be jealous of what I can do now,” he says. “Speed is good. Faster is always better.”

Barnes will play with the device for the first time publicly on March 22 at the Robotic Musicianship Demonstration and Concert at Kennesaw State University’s Bailey Performance Center. The free event is part of the Atlanta Science Festival.

The National Science Foundation funds Weinberg’s research.

Source: Georgia Tech

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