Active control

Until now, we've only considered the vibration isolation provided by the interposition of a highly flexible element that makes vibration propagation difficult by virtue of the impedance discontinuity it constitutes. Apart from the small fraction of energy it dissipates through damping, the support does not alter the initial energy balance of the source system.

A different approach is to introduce a new source of vibration within the support, which will create a vibratory effort that is both synchronous with and antagonistic to the initial vibration: downstream, all vibration will disappear, while additional energy will be added to the source.

The principle of active vibration control is therefore very simple, and has been imagined for a long time. However, it is only now that industrial applications are appearing, as the implementation of...