Method for damping an object, an active damping system, and a lithographic apparatus

摘要

A method for damping an object in two or more degrees of freedom, including measuring a position quantity at each of the two or more measurement locations; extracting from the measured position quantities a measurement signal for each dynamic mode; feeding the measurement signal of a dynamic mode to a controller unit associated with the respective dynamic mode, the controller unit providing for each dynamic mode an output signal on the basis of the respective measurement signal; and providing a control signal to each of the two or more actuators, the control signal for each actuator being based on output signals of one or more controller units.