Controller for a positioning device, method for controlling a positioning device, positioning device, and lithographic apparatus provided with a positioning device

A controller for use in a positioning device, the controller 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 an amplitude and a frequency content of the error signal to obtain a modified error signal;
• and
• generate a control signal to control the positioning device based on the modified error signal, wherein the controller comprises a non-linear filter to selectively modify the error signal, and wherein the non-linear filter is configured to, for error signals having a magnitude in a predefined range, selectively set a gain to a value lower than a value for error signals having a magnitude outside the range.

A positioning device configured to position an object comprising:

• a first part and a second part, the first part movable relative to the second part, the second part arranged to receive the object;
• a position sensor configured to generate a position signal indicative of a position of the object;
• and
• a controller arranged to
• receive a position signal indicative of the position of the object,
• compare the position signal to a set-point signal indicative of a desired position of the object 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, and
• generate a control signal to control the positioning device based on the modified error signal, wherein the controller is arranged to, in order to selectively modify the error signal, (a) perform a first frequency based filtering of the error signal to obtain a filtered error signal, (b) perform an amplitude based modification of the filtered error signal, and (c) perform a second frequency based filtering substantially corresponding to an inverse of the first frequency based filtering.

A lithographic apparatus comprising:

• an illumination system configured to condition a radiation beam;
• a patterning support constructed to support a patterning device, the patterning device being capable of imparting the radiation beam with a pattern in its cross-section to form a patterned radiation beam;
• a substrate support constructed to hold a substrate;
• a projection system configured to project the patterned radiation beam onto a target portion of the substrate;
• and
• a positioning device configured to position at least one of the supports, the positioning device comprising:
• a first part and a second part, the first part movable relative to the second part, the second part arranged to receive the at least one of the supports;
• a position sensor configured to generate a position signal indicative of a position of the at least one of the supports;
• and
• a controller arranged to
• receive a position signal indicative of the position of the at least one of the supports,
• compare the position signal to a set-point signal indicative of a desired position of the at least one of the supports 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, and
• generate a control signal to control the positioning device based on the modified error signal.

A method for controlling a positioning device, the method comprising:

• receiving a position signal indicative of a position of the positioning device;
• comparing the position signal to a set-point signal indicative of a desired position of the positioning device to obtain an error signal;
• selectively modifying the error signal based on both the amplitude and the frequency content of the error signal to obtain a modified error signal;
• and
• generating a control signal for controlling the positioning device based on the modified error signal, wherein selectively modifying the error signal includes
• performing a first frequency based filtering of the error signal to obtain a filtered error signal;
• performing an amplitude based modification of the filtered error signal;
• and
• performing a second frequency based filtering substantially corresponding to an inverse of the first frequency based filtering.

A non-transitory computer readable medium having machine executable instruction, the instructions being executable by a machine to perform a method of controlling a positioning device, the method comprising:

• receiving a position signal indicative of a position of the positioning device;
• comparing the position signal to a set-point signal indicative of a desired position of the positioning device to obtain an error signal;
• selectively modifying the error signal based on both the amplitude and the frequency content of the error signal to obtain a modified error signal;
• and
• generating a control signal for controlling the positioning device based on the modified error signal, wherein selectively modifying the error signal includes
• performing a first frequency based filtering of the error signal to obtain a filtered error signal;
• performing an amplitude based modification of the filtered error signal;
• and
• performing a second frequency based filtering substantially corresponding to an inverse of the first frequency based filtering.