A person using the handrest puts their wrist on a support that can slide horizontally in any direction. Their elbow rests on a support attached to the device.
The Active Handrest allows a person to maintain a steady hand while it senses the position of a hand-grasped tool or the force exerted by the hand – or both. Then, the device's computer software moves the handrest so it "constantly re-centers your fingertips in the center of their dexterous workspace," which Provancher says is "the range over which you can move your fingers and be very precise."
Source-Eurekalert
RAS