Strategies for coupled vibration suppression and energy harvesting

The use of tuned-mass-dampers (TMD) as structural vibration suppressors has been discussed widely over several decades and many parameter selection strategies exist for minimising the displacement of the host structure. Normally these strategies work best when the resonant frequency of the TMD is closely tuned to that of the structural mode that is being targeted. This can be an issue for structures with significant live loads such as slender bridges with heavy traffic. For this type of structure nonlinear or semi-active retunable TMDs have been proposed. In this paper we consider replacing the damper in the TMD with an electrical generator device. In its simplest form this device could be a motor/generator with a resistive load such that the velocity- force relationship is approximately proportional hence mimicking a viscous damper. Here we consider using a voice-coil linear actuator connected to an impedance emulator, which is capable of harvesting, rather than dissipating, some of the vibrational energy. We discuss how this harvested power can then be used to modify the resistive loading in real-time and hence allow a wider bandwidth of operation. The work present both numerical and experimental results and shows some viable strategies for the control and the design of the device