Patent ID: 7039498

Claim:
A method of correcting a robot arm positioning error, the robot arm being operatively connected to an end effector that is operatively coupled with a specimen, the method comprising: providing an end effector having a body including a light source and a light receiver having spaced-apart respective source light path and receiver light path openings between which a light beam propagates along a straight line light transmission pathway, which is employed to determine positions of the end effector relative to the specimen; determining a robot arm old position; recording old position information corresponding to the old position; using the end effector to retrieve the specimen from the old position; employing the old position information to replace the specimen at a new position that is ideally the same as the old position; determining the robot arm new position; recording new position information corresponding to the robot arm new position; and generating correct position information by processing the new position information and the old position information.