An adaptive electrodynamic metamaterial for the absorption of structural vibration

Abstract

This paper presents an adaptive shunted electrodynamic metamaterial, for broadband robust vibration control. The study considers a unit cell of 12 miniature, low-cost proof-mass actuators for the control of vibration in a three degree-of-freedom structure subject to parametric uncertainty. In order to modify their dynamic responses, each actuator is connected to a shunt circuit consisting of a parallel resistor and a switched in/out inductor and capacitor. Provided the impedance of the actuator is cancelled out using a negative impedance, the shunt circuit is capable of tuning the resonance of the actuator up or down in frequency. An adaptive tuning approach is proposed, whereby the shunted actuator resonance frequencies are periodically switched to the centre frequencies of the highest magnitude bins of a real-time frequency analysis of the velocity measured on the structure. This approach is compared to a blind swept tuning method and a fixed-shunt tuning in terms of the robustness to parametric uncertainty, and in practical terms for realisation using analogue or digital shunt impedances.