Patent attributes
A lithographic apparatus includes a first component; an actuator to move the first component relative to a second component; a measurement system to measure at least one of a position, velocity, acceleration and higher order time derivatives of the position; and a control system to control the actuator according to an output of the measurement system. The control system includes various filter branches, each branch acting on an output of the measurement system and determining therefrom characteristic parameters of a different one of a plurality of pre-determined independent variables of a first analytical expression of the output; and a prediction unit that the characteristic parameters and the first analytical expression to provide a version of the output that is time-shifted to at least partially compensate for a delay between a measurement of a property of the second component and the effect of the measurement on an operation of the actuator.
