ACTIVE VIBRATION ISOLATION USING DECENTRALISED VELOCITY FEEDBACK CONTROL

摘要

Active vibration isolation has been investigated both theoretically and experimentally for a four-mount equipment structure, in which electromagnetic actuators were installed in parallel with each of four mounts placed between a flexible equipment and a supporting base structure. Decentralised velocity feedback control was implemented experimentally to actively isolate the vibration at low frequencies up to 200 Hz. In practice, good control performance was observed with a gain margin of about 14 dB. The phase shifts in the electronics of the control loop at low frequencies and the non-collocated installation of the sensor and actuator due to the flexibility of the equipment and base structures were found to be the main threats to the control stability in practice. Control performance in terms of squared velocities of the equipment structure, demonstrated that the multichannel active isolation system can effectively reduce the vibration of the equipment structure over a wide frequency range.