Adaptive and Robust Control Scheme for Active Noise Attenuation

Abstract

The proposed adaptive active noise cancelling system is composed of two controllers: an adaptive feedforward controller and a robust feedback controller. By detecting the noise from the primary noise source, the adaptive controller can generate an artificial sound from the secondary source to reduce the noise level to zero at the observation point. New stability-guaranteed adaptive algorithms are given in time-domain and frequency-domain on a basis of the strictly positive real property of the error model in adaptive control theory, and it is implemented to adjust the coefficient parameters in the HR adaptive controller structure. The role of the robust feedback controller is to compensate multi-path effects and disturbances. The robust controller is designed via the H∞ control theory by taking into account the sensitivity to the disturbances and the model uncertainties in the transfer functions of sound propagation. Numerically and experimentally obtained results exhibited significant improvement on convergency and stability of the adaptive control schemes.