On the use of an SPSA-based model-free feedback controller in active noise control for periodic disturbances in a duct

In this paper, a feedback active noise control (FANC) system using a model-free (MF) controller based on simultaneous perturbation stochastic approximation (SPSA) algorithm is considered. The structure of the FANC system is first described, and the SPSA algorithm is briefly reviewed. Subsequently, the SPSA-based MF control algorithm employed in the FANC system is derived. Computer simulations are carried out to suggest that the SPSA-based MF control algorithm is effective for ANC system and much more efficient than the finite-difference stochastic approximation (FDSA) algorithm. The controller based on the SPSA-based MF control algorithm is implemented on the Texas Instruments digital signal processor (DSP) TMS320VC33. Experimental results show that the proposed scheme is able to significantly reduce periodic disturbances without the need to model the secondary path. At the same time, the simulations and the experimental verification tests also show that the convergence rate of the SPSA-based MF control algorithm is acceptable, and the SPSA-based MF control algorithm has better tracking ability under variable secondary path. This observation implies that the SPSA-based MF controller eliminates the need of modeling of the secondary path for the FANC system.