Who Wants A Few Extra Robot Fingers?

 Bionics  

Researchers at MIT have developed a device, worn around the wrist, that enhances the grasping motion of the human hand with two robotic fingers.

Researchers at MIT have developed a robot that enhances the grasping motion of the human hand. Like another recent project at the university that gives the user an extra set of arms, the new wrist-mounted robot can help you twist a screwdriver, remove a bottle cap, and peel a banana single-handedly.

The device, worn around one’s wrist, works like two extra fingers adjacent to the pinky and thumb. The device's algorithm enables it to move synchronously with the user’s fingers for grasping objects of various shapes and sizes.

“This is a completely intuitive and natural way to move your robotic fingers,” says Harry Asada, the Ford Professor of Engineering in MIT’s Department of Mechanical Engineering. “You do not need to command the robot, but simply move your fingers naturally. Then the robotic fingers react and assist your fingers.”

"You do not need to command the robot, but simply move your fingers naturally. Then the robotic fingers react and assist your fingers."

Asada says, with some training people may come to perceive the extra bionic fingers as part of their body — “like a tool you have been using for a long time, you feel the robot as an extension of your hand.” He hopes that the two-fingered robot may assist people with limited dexterity in performing routine household tasks, such as opening jars and lifting heavy objects. He and graduate student Faye Wu presented a paper on the robot this week at the Robotics: Science and Systems conference in Berkeley, California.

The robot, which the researchers have dubbed “supernumerary robotic fingers,” consists of actuators linked together to exert forces as strong as those of human fingers during a grasping motion.

To develop an algorithm to coordinate the robotic fingers with a human hand, the researchers first looked to the physiology of hand gestures, learning that a hand’s five fingers are highly coordinated.

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The researchers hypothesized that a similar “biomechanical synergy” may exist not only among the five human fingers, but also among seven. To test the hypothesis, Wu wore a glove outfitted with multiple position-recording sensors, and attached to her wrist via a light brace. She then scavenged the lab for common objects, such as a box of cookies, a soda bottle, and a football.

Wu grasped each object with her hand, then manually positioned the robotic fingers to support the object. She recorded both hand and robotic joint angles multiple times with various objects, then analyzed the data, and found that every grasp could be explained by a combination of two or three general patterns among all seven fingers.

The researchers used this information to develop a control algorithm to correlate the postures of the two robotic fingers with those of the five human fingers. Asada explains that the algorithm essentially “teaches” the robot to assume a certain posture that the human expects the robot to take.

Down the road, Asada says the robot may also be scaled down to a less bulky form. “This is a prototype, but we can shrink it down to one-third its size, and make it foldable,” Asada says. “We could make this into a watch or a bracelet where the fingers pop up, and when the job is done, they come back into the watch. Wearable robots are a way to bring the robot closer to our daily life.”




SOURCE  MIT

By 33rd Square

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