Device for positioning control

A device for positioning control, comprising:

• a base member;
• a guide member provided on said base member;
• a Y stage movable on said base member in a y-axis direction, along said guide member;
• an X stage movable in an x-axis direction relative to said Y stage;
• a mirror disposed on said X stage, for measuring position of the Y stage;
• a feedback loop for controlling movement of said Y stage on the basis of an amount of movement, measured by said mirror;
• and
• an acceleration sensor disposed on said X stage, at a position adjacent to said mirror.

A positioning control method comprising the steps of:

• providing a major feedback loop for providing signals to control movement of a movable table and a minor feedback loop for providing signals to control vibration of the movable table;
• controlling the movement of the movable table in accordance with the signals provided by the major feedback loop;
• detecting acceleration of the movement of the movable table through an acceleration sensor provided on the movable table, and producing an acceleration signal from the acceleration sensor;
• and
• extracting from the acceleration signal, in the minor feedback loop, a signal having a frequency in a particular region that is used in controlling the vibration of the movable table.

A positioning control device comprising:

• a movable table mechanism comprising a movable table;
• measuring means for measuring position of said movable table and for producing a measurement signal which changes with the position of said movable table;
• a major feedback loop for controlling movement of said movable table on the basis of the measurement signal produced by said measuring means;
• an acceleration sensor provided on said movable table for producing an acceleration signal;
• and
• a minor feedback loop for controlling vibration of said movable table on the basis of the acceleration signal produced by said acceleration sensor, said minor feedback loop comprising a low-pass filter having a cut-off frequency which is substantially the same as a resonance frequency of said movable table mechanism.

A positioning control device comprising:

• a movable table mechanism comprising a movable table;
• measuring means for measuring position of said movable table and for producing a measurement signal which changes with the position of said movable table;
• a major feedback loop for controlling movement of said movable table on the basis of the measurement signal produced by said measuring means;
• an acceleration sensor provided on said movable table for producing an acceleration signal;
• and
• a minor feedback loop for controlling vibration of said movable table on the basis of the acceleration signal produced by said acceleration sensor, said minor feedback loop comprising a band-pass filer for extracting a resonance frequency of said movable table mechanism as well as a jerk signal obtained by differentiating the acceleration signal passing through said band-pass filter.