Analysis of effort constraint algorithm in active noise control systems

In ANC systems, in case of loudspeakers saturation, the adaptive algorithm may diverge due to nonlinearity. The most common algorithm used in ANC systems is the FXLMS which is especially used for feed-forward ANC systems. According to its mathematical representation, its cost function is conventionally chosen independent of control signal magnitude, and hence the control signal may increase unlimitedly. In this paper, a modified cost function is proposed that takes into account the control signal power. Choosing an appropriate weight can prevent the system from becoming nonlinear. A region for this weight is obtained and the mean weight behavior of the algorithm using this cost function is achieved. In addition to the previous paper results, the linear range for the effort coefficient variation is obtained. Simulation and experimental results follow for confirmation.