Active/passive vibration isolation with multi-axis transmission control: Analysis and experiment

It is necessary to cut off all vibration transmission paths for an active vibration isolation system. A greater suppression of local responses will result in a better overall attenuation. In order to realize impediment at possible transmission paths, a new scenario of multi-axis transmission control is proposed, in which the active/passive isolator attenuates vibration transmission at multi-degrees of freedom by vertical and horizontal actuators mounted orthogonally on the intermediate inertial mass. This scenario is able to weaken the cross-coupling of control action between isolators by the passive parts. In order to investigate the characteristics of multi-axis transmission control, the dynamic model of a partitioned isolation system with one active/passive isolator is established and the involved transmission control is analyzed. The numerical results show that the foundation vibration can be attenuated along with the decrease of vibrations of the intermediate inertial mass. It is further revealed by experimental results that the multi-axis transmission control at the intermediate inertial mass is necessary to achieve sufficient vibration attenuation in the foundation, whereas the control in a single axis is ineffective. These verified results imply that the active/passive isolation with local transmission path control makes it possible to apply decentralized control in a large active vibration isolation system.