POSITION CONTROL SYSTEM, LITHOGRAPHIC APPARATUS, AND METHOD TO CONTROL POSITION OF MOVABLE OBJECT

摘要

PROBLEM TO BE SOLVED: To provide a position control system and/or a method for a movable object of a lithographic apparatus which can increase the accuracy and/or speed of position control of the movable object.

SOLUTION: A position control system to control the position of a movable object includes a position measurement system configured to determine an actual position related quantity of the movable object; a set-point generator to provide a position related set-point signal of the movable object; a comparator to provide an error signal on the basis of a comparison of the actual position related quantity and the position related set-point signal; a controller to provide a control signal on the basis of the error signal; a feed-forward device to provide a feed-forward signal on the basis of the position related set-point signal; and one or more actuators to act on the movable object on the basis of the control signal and the feed-forward signal. The feed-forward device includes a disturbance force correction table including estimated values of disturbance forces exerted on the movable object in dependence upon a position of the movable object.

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