A METHOD FOR DAMPING AN OBJECT, AN ACTIVE DAMPING SYSTEM, AND A LITHOGRAPHIC APPARATUS

摘要

A METHOD FOR DAMPING AN OBJECT, AN ACTIVE DAMPING SYSTEM, ANDA LITHOGRAPHIC APPARATUS ABSTRACT A method for damping an object in two or more degrees of freedom, includingmeasuring 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.Figure 3