Patent attributes
A control system to control a position parameter of a stage in a lithographic apparatus includes a stage controller to control a position parameter of the stage in at least a first direction. The control system includes a disturbance torque estimator to estimate a disturbance torque on the stage, the disturbance torque about an axis extending in a second direction, the second direction being substantially perpendicular to the first direction. The control system includes a correction signal calculator, the correction signal calculator provided with the estimated disturbance torque and a signal representative of a position of the stage in a third direction, the third direction being substantially perpendicular to the first and second directions. The correction signal calculator determines a feedforward correction signal to correct a position error of the stage in the first direction due to the disturbance torque, the feedforward correction signal to be fed to the stage.
