Active anti-vibration apparatus

An active anti-vibration apparatus comprising:

• an anti-vibration table, supported by an anti-vibration supporting mechanism, for mounting precision equipment;
• a plurality of actuators for applying control power to said anti-vibration table;
• a plurality of vibration detection means for detecting vibrations of said anti-vibration table;
• a low-pass filter for transmitting frequency components which are lower than a predetermined frequency out of signals outputted from said vibration detection means;
• a high-pass filter for transmitting frequency components which are higher than a predetermined frequency out of the signals outputted from said vibration detection means;
• motion mode extraction means for extracting vibration signals of motion modes on the basis of extracted signals having the frequency components which are lower than the predetermined frequency obtained as output signals from said low-pass filter;
• first compensation calculation means for compensating the vibration signals from said motion mode extraction means;
• thrust distribution means for distributing a compensation signal for each motion mode obtained by said first compensation calculation means as driving instruction signals of said plurality of actuators;
• second compensation calculation means for compensating extracted signals having the frequency components which are higher than the predetermined frequency obtained as output signals from said high-pass filter;
• and
• means for adding output signals from said thrust distribution means and said second compensation calculation means and feeding back the added result to said actuators.