A robotic positioning system that cooperates with a sensing system to
correct robot motion is provided. The sensing system is decoupled from
the sensors used conventionally to control the robot's motion, thereby
providing repeatable detection of the robot's true position. In one
embodiment, the positioning system includes a robot, a controller, a
motor sensor and a decoupled sensor. The robot has at least one motor for
manipulating a linkage controlling the displacement of a substrate
support coupled thereto. The motor sensor is provides the controller with
motor actuation information utilized to move the substrate support. The
decoupled sensor provides information indicative of the true position the
substrate support that may be utilized to correct the robot's motion.
