Design and closed-loop control of an electroactive polymer-based tunable Helmholtz resonator

Abstract

A Helmholtz resonator is a passive acoustic resonator used to control a single frequency resulting from the cavity volume and the resonator neck size. The aim of the proposed study is to present a new concept and strategy of tunable Helmholtz resonator in order to enhance acoustic performances in lower frequencies (<500 Hz). The proposed concept consists in replacing the resonator rigid front plate by an electroactive polymer (EAP) membrane. When an electric field is applied, a change is made in the mechanical properties of the EAP membrane which induce a resonance frequency shift. A closed-loop control algorithm is developed to allow a real-time adaptability. Experimental measurements are performed on the developed prototype to determine the potential of this concept in term of acoustic absorption and Transmission Loss for low-frequency.