Vibration damping apparatus

A vibration damping apparatus for isolating vibrations of an installation floor comprising:

• a vibration-isolating table for placing an object thereon which is to be isolated from vibrations;
• an air spring for mounting on an installation floor and supporting said vibration-isolating table to bear a substantial proportion of the weight of the object, for attenuating vibrations from said installation floor;
• an air pressure controller for controlling an air pressure of said air spring;
• a displacement sensor for detecting a relative displacement between said vibration-isolating table and said installation floor and supplying a signal indicative of the detected relative displacement to said air pressure controller;
• a spring element acting between said vibration-isolating table and said installation floor for positioning said vibration-isolating table in a horizontal direction;
• an electromagnet disposed between said vibration-isolating table and said installation floor for actively attenuating vibrations of said vibration-isolating table;
• an acceleration sensor for detecting an acceleration of said vibration-isolating table;
• and
• a controller for controlling said electromagnet based on an acceleration signal from said acceleration sensor, which is representative of an acceleration of said vibration-isolating table, to actively attenuate vibrations of the vibration-isolating table.