Assessment of an active dynamic vibration absorber

The present paper addresses the attenuation of mechanical vibrations using active dynamic vibration absorbers (DVAs). Besides the typical parameters of passive DVAs (inertia, stiffness and damping), active DVAs possess an actuator placed between the primary mass and the absorber mass, which applies a control force according to an appropriate control law. This way, active DVAs can be tuned to any value of the excitation frequency within a relatively large frequency band by modifying the control force, without any change in the values of the passive parameters. A particular configuration of active DVA is proposed, based on a control law in which the control force is expressed as a linear combination of the relative displacement, velocity and acceleration responses of the DVA mass with respect to the primary system. The basic formulation is first presented, including stability analysis, DVA tuning by frequency response zero placement and optimal frequency response shaping. Finally, the main features and performance of the active DVA are assessed through numerical simulations.