Stability analysis of secondary path estimation during FSF-based feedback control

A pure feedback controller alternative is proposed to the feedforward filtered reference least mean method for active noise control under periodic disturbances. There is no need for pre-modelling of any dynamics. The scheme is a frequency selective filter based controller with secondary plant estimation during control. For each major disturbance signal, a complex controller gain of the frequency component is computed and a complex gain for the plant dynamics is updated. The main contribution in this paper is the proof of stability. The controller was implemented on a laboratory sound experiment. The controlled sound wave was measured with a microphone. Next to the disturbance speaker, the controlled speaker was placed to generate the destructive secondary sound wave. An output attenuation of about 37dB was achieved, clearly showing the usefulness of the approach.