Active oscillation isolation system by means of a hysteresis-free pneumatic bearing

An arrangement for oscillation isolation of a mass comprising:

• an air bearing for supporting the mass, wherein the mass comprises a lithographic system;
• a device for supplying pressure to the air bearing, the device having a compressed-air source and a control valve for a compressed-air flow to be supplied to the air bearing;
• a pneumatic control loop for controlling a moving valve element of the control valve;
• an actuator for oscillation-suppressing support of the mass;
• a sensor for detecting the oscillation state of the mass;
• an oscillation suppression control loop for controlling the actuator as a function of the sensor;
• and
• a dither signal transmitter for transmitting a dither signal to both:
• i) the control valve, in order to influence the movement state of the valve element, resulting in dither vibration of the mass being produced, and
• ii) a dither compensation circuit;
• wherein the dither compensation circuit is for controlling, based on the dither signal from the dither signal transmitter, the actuator, in order to suppress the dither vibration of the mass,
• wherein the dither compensation circuit and the oscillation suppression control loop are connected to the sensor for detecting the oscillation state of the mass, and
• wherein the dither compensation circuit and the oscillation suppression control loop are connected via an addition element to the actuator for oscillation-suppressing support of the mass.