Alternating the twin rotor damper between two modes of operation to eliminate small vibrations

Abstract

In previous research, the twin rotor damper (TRD), an active mass damper, was presented. In a preferred, energy-efficient mode of operation, the continuous rotation mode, two eccentric control masses rotate with constant angular velocities about two parallel axes in opposite directions. The resulting centrifugal forces combine into a directed harmonic control force that can be used for the control of structural vibrations. In another, more power-demanding mode of operation, the swinging mode, both control masses oscillate about certain angular positions. For both modes of operation, corresponding control algorithms have been developed. Furthermore, it has been found that the continuous rotation mode is not efficient for the damping of small vibrations, whereas the swinging mode can bring small vibrations to rest. In this paper, a control algorithm is presented, which uses the continuous rotation mode for large vibrations and the swinging mode for small vibrations. To validate the control algorithm, the TRD is numerically and experimentally applied on a single degree of freedom oscillator. The efficiency of the algorithm is studied for free vibrations.