Secondary Sound Source Design And Control Algorithm Research Of Active Noise Reduction Seat

With the gradual attention of noise pollution in recent years,active noise control technology has been more studied and applied.As a type of scene that is more seriously affected by noise,the active noise control technology of train carriages and aircraft cabins is also developing.Among them,the active noise reduction seat is a noise reduction system suitable for such scenarios.But based on the electroacoustic devices and control algorithms currently used,it has the shortcomings of high computing amount and low stability in the above multi-seat scenarios.In view of these shortcomings,this paper studies the active noise control system using a parametric array loudspeaker with strong directivity as the secondary source,and proposes an effective prediction model and improvement scheme for the design of the secondary source and the improvement of the corresponding control algorithm.The key research contents are as follows:(1)Aiming at the problems of control sound field overflow,calculation increase and inter-system interference of the current active noise reduction seat system in multi-seat scenarios,the improvement effect of using parametric array loudspeaker as a secondary source is analyzed,and the feasibility of the scheme is verified by building a three-seat system simulation environment.(2)Aiming at the problem of low efficiency of secondary path modeling using adaptive filtering method in multi-channel active noise control system,a hybrid filtering modeling method combining adaptive filtering method and matched filtering method is proposed,and the efficiency improvement brought by this method is verified by simulation,and the applicability of the method is analyzed.(3)To meet the flexible design requirements of the parametric array loudspeaker in the active noise reduction seat system,it is necessary to accurately predict the directivity of the sound beam.In view of the existing numerical methods and analytical models that are difficult to meet the application requirements due to the calculation amount and limitations,two extended convolution directivity models are proposed to realize the beam directivity prediction of parametric array loudspeaker based on amplitude modulation,and the effectiveness of the proposed model is verified by building a simulation and experimental system.(4)Aiming at the general noise reduction effect of the classical FxLMS algorithm when using the parametric array loudspeaker as the secondary source,the performance of the FeLMS algorithm in this system is compared and studied.And the FeLMS algorithm modeled online is proposed,so that the system has a certain ability to track the change of the secondary path while maintaining better noise reduction effect.