Home TECH NEWS This brain-controlled robotic arm can twist, grasp and feel

This brain-controlled robotic arm can twist, grasp and feel



The brain is two-way: it sends signals to other parts of the body while receiving information, telling it to take action.Even an action that looks as simple as holding a cup will call your brain to control your hand muscles and listen To the nerves of your fingers.

Because Copland’s brain was not injured in his accident, in theory it can still manage this input and output dialogue. But most of the electrical information from his body’s nerves did not reach the brain. When the Pittsburgh team recruited him into their research, they wanted to devise a solution. They believe that the brain of a paralyzed person can either stimulate the robotic arm or be stimulated by electrical signals from the robotic arm, and ultimately interpret this stimulation as the sensation of being touched by their own hands. The challenge is to make everything natural. When Copeland wants to twist, the robot’s wrist should twist; when he wants to grasp, the hand should be closed; When the robot’s little finger touches a hard object, Copeland should feel it on his little finger.

In the four microelectrode arrays implanted in Copland’s brain, two grids read the motion intention from his motor cortex to command the robotic arm, and two grids stimulate his sensory system. From the beginning, the research team knew that they could use BCI to create tactile sensations for Copeland by simply supplying electrical current to these electrodes—no actual touch or robotics required.

To build this system, the researchers took advantage of the fact that Copeland’s right thumb, index finger, and middle finger retained some sensations. When he was sitting in a magnetic brain scanner, the researchers rubbed a cotton swab there, and they discovered which specific contours of the brain corresponded to these fingers. Then, the researcher decoded his intention to move by recording the brain activity of a single electrode as he imagined a particular movement. He felt it when they switched on the electric current to a specific electrode in his sensory system. To him, this feeling seemed to come from the roots of his fingers, near the top of his right palm. It felt like natural pressure or warmth, or strange tingling-but he had never experienced any pain. “Actually I just stared at my hand as if I was saying,’Man, it really feels like someone might poke there,'” Copland said.

Once they have determined that Copland can experience these sensations, and the researchers know which brain regions should be stimulated to produce sensations in different parts of his hand, the next step is to get Copland used to control the robotic arm. He and the research team set up a training room in the laboratory with posters of Pac-Man and cat memes. Every Wednesday, the researcher will connect the electrode connector from his scalp to a set of cables and a computer, and then they will time the blocks and spheres as he grabs them, moving them from left to right. After a few years, he became very good.He even Demonstrated the system For the then President Barack Obama.

But then, Collinger said, “His high-level performance is a bit stagnant.” It takes about five seconds for a non-paralyzed person to complete the task of moving objects. Copeland can sometimes finish in 6 seconds, but his median time is about 20 seconds.

In order for him to tide over the difficulties, it is time to try to provide him with real-time touch feedback from the robotic arm.

Human fingers can feel pressure, and the resulting electrical signals are transmitted from the hand to the brain along the linear axons. The team reflected the sequence by placing sensors on the fingertips of the robot. But objects do not always touch the fingertips, so a more reliable signal must be provided from elsewhere: the torque sensor at the bottom of the robotic finger.


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