Identification of Acoustic Impedance Using a Simple Genetic Algorithm

Abstract

A new identification method for acoustic impedance of an acoustic duct system is developed in this study such that a proper working model for active noise control can be acquired. A bite-length acoustic duct system with an exciting input at one end and a partially reflective boundary condition represented by its acoustic impedance at the other end is considered. Two microphones placed at two different locations in the kite-length duct are used to obtain measured frequency responses. A simple genetic algorithm in corporation with an acoustic model is then utilized to identify the acoustic impedance from the measured frequency responses. Advantage of this proposed identification method is that the two microphones can be arbitrarily mounted. Both computer simulation and experimental results demonstrate the effectiveness and feasibility of the proposed identification method.