Adapting an MSE Controler for Active Noise Control in Nonstationary Noise Statistics.

Annea Barkefors and Mikael Sternad , Uppsala University.

43rd International Congress on Noise Control Engineering, Inter.noise 2014, Melbourne, Australia, November 16-19 2014.

Abstract:

In feedforward active noise control, a primary noise signal is used to generate control signals via a set of loudspeakers. In problems where many loudspeakers are used, it becomes difficult to adjust the controller filters to fast changing spectral properties of broadband primary noise signals. Many parameters then need to be readjusted simultaneously, which limits the tracking performance of e.g. filtered-x LMS adaptation algorithms.

Here we propose and evaluate two feedforward control methods based on linear quadratic gaussian control that adapt to the often time-varying statistical properties of the feedforward noise signal, in a partly indirect adaptive design. For both proposed methods, the time is divided in batches and the control laws are updated for each time batch based on repeated estimates of the noise statistics.

In the first method, the estimates of the noise statistics are incorporated into the controller, which is updated for each batch, whereas in the second method the controller is kept constant and a predictor for the noise is updated. The first method seems promising, and shows a gain in attenuation of about 5 dB over a controller that disregards the feedforward noise statistics. The second method, however, shows no such advantage.

Related publications:

Licentiate thesis by Annea Barkefors, May 2014

Paper at ACC 2012 on feedforward active noise control design for car interiors.

Paper in IEEE TASLP 2014 on design and analysis of linear quadratic gaussian feedforward controllers for active noise control.

Robust Sound Field Control for Audio Reproduction. A polynomial approach to discrete-time acoustic modeling and filter design.
PhD Thesis by Lars-Johan Brännmark, 2011.