CONTROLLER FOR A POSITIONING DEVICE, METHOD FOR CONTROLLING A POSITIONING DEVICE, POSITIONING DEVICE, AND LITHOGRAPHIC APPARATUS PROVIDED WITH A POSITIONING DEVICE

摘要

A controller for a positioning device is constructed and arranged to receive a position signal indicative of a position of the positioning device, compare the position signal to a set-point signal indicative of a desired position of the positioning device to obtain an error signal, selectively modify the error signal based on the amplitude and the frequency content of the error signal to obtain a modified error signal, generate a control signal for controlling the positioning device on the basis of the modified error signal. The controller may be applied to control a positioning device in a lithographic apparatus.