摘要 |
An actuator system is disclosed having a first actuator (XP1) and a second actuator (XP2) configured to control a relative position of optical components of a lithographic apparatus. The first actuator (XP1) is configured to provide a displacement, parallel to an actuation direction, between a mounting point of a first component of the lithographic apparatus and a second component of the lithographic apparatus. The second actuator (XP2) is configured to provide a displacement parallel to the actuation direction between a reference mass (M1) associated with the second actuator (XP2) and the mounting point of the first component of the lithographic apparatus. The second actuator (XP2) may be driven such that the displacement between the second actuator (XP2) and the reference mass (M1) increases the apparent stiffness of the first actuator (XP1). |