A new method for multiple frequency vibration absorption

A class of actively tuned vibration absorbers is presented. The absorber substructure is controlled using an unconventional position feedback with time delay. This control sensitizes the absorber at multiple frequencies which are time varying. The text discusses a new formation for the feedback, which converts the absorber into multiple frequency delayed resonator. This resonator, in turn, acts as a perfect absorber of vibration at its resonant frequencies. One major advantage in this method is the use of relative position feedback from within the absorber. These measurements are monitored independently from the primary structure and they can be made in the absorber´s enclave. Typical system characteristics are demonstrated using an example. A single-degree-of-freedom primary systems and a two-degrees-of-freedom absorber are taken into consideration as dual frequency suppression for a case study