Nikon Corporation

Gabor D Szoboszlay

Andrew J Hazelton

Bausan Yuan

Kazuhiro Hirano

Yi-Ping Hsin

Kazuo Masaki

Ryoichi Kawaguchi

John Peterson

Christopher B Smith

Embodiments of the invention relate to a cable force feedforward approach that takes into account the cable force in the counter-mass trajectory computation to reduce or eliminate vibration of the lens body caused by the cable force disturbance and corrective force exerted by the trim motors. In one embodiment, a method provides cable force feedforward control for a counter-mass of a stage with a cable connected to the counter-mass and using the cable force feedforward control to control one or more trim motors to produce a trim motor output force to be applied to the counter-mass, the counter-mass moving in response to a reaction force from movement of the stage. The method comprises measuring a counter-mass position y of the counter-mass in response to forces applied to the counter-mass; measuring a cable force &#x192; exerted on the counter-mass by the cable which is connected to the counter-mass; generating a cable force function {circumflex over (&#x192;)}(y, {dot over (y)}) of the measured cable force &#x192; versus the counter-mass position y; and computing the trim motor output force u as where w is a weighting function having a value from 0 to 1 and is selected for optimization.

Minimum force output control method for counter-mass with cable

A stage assembly ( ) for moving a device ( ) along an X axis and a Y axis includes a stage base ( ), a device table ( ), a stage mover assembly ( ), a measurement system ( ), and a control system ( ). The stage mover assembly ( ) includes a pair X guide movers ( ) ( ) and a Y table mover ( ). The measurement system ( ) includes a first X system ( ) and a second X system ( ). The control system ( ) receives the position signals from the measurement system ( ) and directs current to the X movers ( ) ( ) to move the device table along the X axis. The control system ( ) can be designed to not skip any servo cycles during switching of position signals.

System and method for switching position signals during servo control of a device table

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Santa Clara, CA, United States of America

Gabor D Szoboszlay