Abstract: A lithographic apparatus or frame assembly, comprising: a first and second pneumatic support, being arranged to control position of a frame, each of said pneumatic supports accommodating a pressure chamber; a frame position control system, comprising; a first position sensor device, configured to generate measurement data relating to the position of the frame; a first pressure controller, configured to control the pressure in the pressure chamber of the first pneumatic support on the basis of the measurement data generated by the first position sensor device; a pressure differential sensor device, configured to generate data relating to the difference between the pressure in the pressure chambers of the first and the second pneumatic support; a second pressure controller, configured to control the pressure in the pressure chamber of the second pneumatic support on the basis of the measurement data from the pressure differential sensor device.

Abstract: The invention provides a pneumatic support device for a lithographic apparatus and a lithographic apparatus with such support device. The support device comprises a gas spring. The gas spring comprises a suspending part, a suspended part, and a pressure chamber configured for supporting the suspended part relative to the suspending part. The support device further comprises an actuator configured for positioning the suspended part relative to the suspending part, an acceleration sensor configured for generating a first sensor signal representative for the acceleration of the suspending part, a pressure sensor configured for generating a second sensor signal representative for the pressure in the pressure chamber, and a control unit.

Abstract: The present invention relates to a lithographic apparatus, comprising: —a base frame (10), adapted for mounting the lithographic apparatus (1) on a support surface (9), —a projection system (20) comprising: —a force frame (30), —an optical element (21) which is moveable relative to the force frame, —a sensor frame (40), which is separate from the force frame, —at least one sensor which is adapted to monitor the optical element, comprising at least one sensor (25) element which is mounted to the sensor frame, —a force frame support (31), which is adapted to support the force frame on the base frame, —an intermediate frame (45), which is separate from the force frame, —a sensor frame coupler (41), which is adapted to couple the sensor frame to the intermediate frame, —an intermediate frame support (46), which is separate from the force fame support and adapted to support the intermediate frame on the base frame.