tatwood
01-03-2007, 11:56 PM
In late 2006, the Rehabilitation Institute of Chicago (RIC) unveiled the world’s first “Bionic Woman,” Claudia Mitchell. The RIC neuro-controlled Bionic Arm allows an amputee to move a prosthetic arm as if it is a real limb simply by thinking. The arm also empowers patients with more natural movement, greater range of motion and restores lost function. The technology was developed by Todd Kuiken, M.D., Ph.D., director of RIC’s Neural Engineering Center for Bionic Medicine, and a team of leading rehabilitation experts with the support of grants from the National Institutes of Health (NIH).
Blair Lock, who has an electrical and biomedical Masters from the University of New Brunswick, and who is on the Bionic Arm team, notes that everything is commanded by a digital signal processor from Texas Instruments that is optimized for digital motor control. It directs five of the six motors in the arm. The elbow motor is a brushless LTI motor. The hand is made in China with two degrees of freedom for gripping and wrist flexion/extension; both motors are PWM controlled. A NiMH and a Lithium battery are used in the arm.
Nerves are surgically transferred to chest muscles that are no longer being used, given the absence of the arm. The nerves that used to tell your hand to open or close are sewn onto chest muscles. Clinically, the robot arm is getting myeoelectric signals from motor nerves for robot motor inputs, i.e., muscle electrical energy from under the skin, using a bipolar setup with two stainless steel electrodes on multiple sites. This is a direct routing of a mental hand-open command to a robotic-arm hand-open command.
Blair notes “we were surprised that some of the sensory nerve components also reintegrated into sensory areas in the skin. When you touch the area on the chest it feels like the missing hand or whatever area is being touched. Additionally, these sensory inputs seem to be normal—with gradients in pressure as well as hard-soft; sharp-dull and warm-cold. This sparked the idea that we could feed this information back to the prosthesis user. Initial experimental results are encouraging and we are still trying to quantify this feedback.”
Look to a future issue of Robot for more details on the first true bionic arm!
Blair Lock, who has an electrical and biomedical Masters from the University of New Brunswick, and who is on the Bionic Arm team, notes that everything is commanded by a digital signal processor from Texas Instruments that is optimized for digital motor control. It directs five of the six motors in the arm. The elbow motor is a brushless LTI motor. The hand is made in China with two degrees of freedom for gripping and wrist flexion/extension; both motors are PWM controlled. A NiMH and a Lithium battery are used in the arm.
Nerves are surgically transferred to chest muscles that are no longer being used, given the absence of the arm. The nerves that used to tell your hand to open or close are sewn onto chest muscles. Clinically, the robot arm is getting myeoelectric signals from motor nerves for robot motor inputs, i.e., muscle electrical energy from under the skin, using a bipolar setup with two stainless steel electrodes on multiple sites. This is a direct routing of a mental hand-open command to a robotic-arm hand-open command.
Blair notes “we were surprised that some of the sensory nerve components also reintegrated into sensory areas in the skin. When you touch the area on the chest it feels like the missing hand or whatever area is being touched. Additionally, these sensory inputs seem to be normal—with gradients in pressure as well as hard-soft; sharp-dull and warm-cold. This sparked the idea that we could feed this information back to the prosthesis user. Initial experimental results are encouraging and we are still trying to quantify this feedback.”
Look to a future issue of Robot for more details on the first true bionic arm!