Adaptive Resonant Shunts

The damping performance of resonant multi-mode shunts is highly sensitive. If the parameters of the piezoelectric transducer or the mechanical structure change, then the resonant shunt gets miss-tuned and loses its damping. Therefore, resonant shunts need to be tuned online.

A relative phase adaptation to online-tune resonant multi-mode shunts was proposed [1], [2]. It is based on the calculation of the relative phase between a reference signal and shunt current. However, direct calculation of the phase is not required. The relative phase adaptation can be expressed as

.

Experimental results validated the performance of the relative phase adaptation, where the resonance frequency of the mechanical structure was changed by an additional weight on the structure.

(Measured magnitude of the transfer-function from disturbance to velocity on a beam as a function of time)

(Layout of the adaptive shunt circuit)