Merging extremum seeking and self-optimizing narrowband interference canceller - overdetermined case

Abstract

Active cancellation systems rely on destructive interference to achieve rejection of unwanted disturbances entering the system of interest. Typical practical applications of this method employ a simple single input, single output arrangement. However, when a spatial wavefield (e.g. acoustic noise or vibration) needs to be controlled, multichannel active cancellation systems arise naturally. Among these, the so-called overdetermined control configuration, which employs more measurement outputs than control inputs, is often found to provide superior performance. The paper proposes an extension of the recently introduced control scheme, called self-optimizing narrowband interference canceller (SONIC), to the overdetermined case. The extension employs a novel variant of the extremum-seeking adaptation loop which uses random, rather than sinusoidal, probing signals. This modification simplifies design of the controller and improves its convergence. Simulations, performed using a realistic model of the plant, demonstrate improved properties of the new controller.