Active vibration isolation using decentralized velocity feedback control

Isolating a piece of delicate equipment from the vibration of a base structure is of practical importance in a number of engineering fields. Examples are the isolation of instrument boxes in aeroplane and the isolation of telescopes and antennas in satellites. In the majority of cases, the base is flexible and vibrates with an upredictable waveform which has a broadband spectrum. The active isolation of a vibration-sensitive equipment structure from a vibrating base is studied in this paper. Passive anti-vibration mounts are widely used to support the equipment and protect it from severe base vibration. However, conventional passive mounts suffer from an inherent trade-off between high frequency isolation and amplification of vibration at the fundamental mounted resonance frequency. General the best isolation performance is achieved by using an active system in combination with a passive mount, where the fundamental resonance can be actively controlled without reducing the high frequency performance