A self-tuning electromagnetic vibration absorber with adaptive shunt electronics

Abstract

Tuned vibration absorbers (TVAs) are effective devices for vibration control in the presence of tonal excitation, but when the properties of the host structure change or the excitation frequency varies they become detuned and their performance can degrade to an unacceptable level. It is therefore desirable that the properties of the TVA can adapt to maintain optimal tuning. In this paper an electromagnetic device with an adaptive synthetic shunt impedance which provides a controllable effective mechanical stiffness and damping is proposed. The shunt impedance, comprising resistance and capacitance, is implemented digitally and can be altered in real-time to allow the system to adapt. A model-based feedforward controller is designed and implemented to adapt both the shunt resistance and capacitance to ensure the tuned frequency of the vibration absorber tracks the excitation frequency. This ensures that the system has optimal performance throughout a large range of excitation frequencies. Simulations and experimental results show that the adaptive controller can successfully adapt the system to track a variable excitation frequency and hence demonstrates better performance than the equivalent non-adaptive undamped system, as well as an optimally tuned damped system.