Patent ID: 7649613

Claim:
A lithographic apparatus comprising: a component that is configured to move relative to a reference frame within the lithographic apparatus; a first actuator configured to exert a force on the component so as to move the component to a desired position relative to said reference frame within the lithographic apparatus; a reaction mass mounted to the component; a second actuator located between the component and the reaction mass such that the second actuator is configured to exert a force between the component and the reaction mass; and a controller configured to control the second actuator such that a reaction force exerted on the component by the second actuator can adjust at least one of a position, velocity or acceleration of the component relative to said reference within the lithographic apparatus, wherein the controller is configured to determine a difference between a force intended to be applied to the component by the first actuator and an actual force applied to the component by the first actuator; and to control the second actuator such that the reaction force exerted on the component corresponds to said difference.