Feasibility study on decentralized control system for active acoustic shielding

Convergence of perfectly decentralized control system for Active Acoustic Shielding (AAS) of urban noise is studied. In our previous study, we proposed AAS and proved its feasibility on noise reduction with small windows. However, the typical window size in the house requires large number of AAS cells and a simplified control algorithm is necessary for practical implementation. In previous study, we suggested a partial decentralized adaptive control algorithm of AAS that employs only neighboring error signals for each channel, and confirmed its feasibility. In this study, we investigate the feasibility of the fully decentralized control system for AAS under the assumptions that the primary noise is plane wave that propagates from vertical incidence. It was found that the fully decentralized control system could obtain a stable convergence by appropriately modeling the secondary paths with the sum of the secondary paths from all secondary speakers to the error microphone right in front of each AAS cell. Therefore, the convergence behavior of the fully decentralized multichannel control system can be modeled similar to the single channel control system. Finally, we conduct experiments to verify the feasibility of the decentralized control system.