Patent ID: 7073644

Claim:
An anti-vibration system for supporting a table, comprising: a gas spring for supporting the table; pressure control means for controlling an internal pressure of said gas spring; a pressure sensor for detecting a supply pressure to be supplied to said pressure control means; control means for controlling said pressure control means in accordance with a detection output signal of said pressure sensor; and variable gain compensation means for performing gain compensation to a control signal of said pressure control means in accordance with a detection signal of said pressure sensor, wherein, when a pressure which is in a balanced state is denoted by P SO , an input signal, with an assumption that the supply pressure is P SO and is unchangeable, is denoted by i 0 , and a pressure detected by said pressure sensor is denoted by P S , said variable gain compensation means produces an input signal i in accordance with the following equation: i =( P SO /P S )Ã—i 0 .