Research And Application Of Active Noise Hybrid Structure Control System

With the development of social industrialization,noise pollution is becoming more and more serious,and it has caused certain harmful effects on human body and psychology.Noise affects people's hearing,makes people feel irritable,and seriously affects human life.Therefore,reducing noise is a very significant issue.Active and passive noise control are two effective methods for dealing with noise pollution today.Passive noise control mainly uses some sound absorbing materials or sound insulation materials to reduce noise.Its main high frequency noise has a good noise reduction effect,and it has no obvious effect on low frequency noise.Active noise control(ANC)uses the Young's interference principle to artificially generate an output signal that is opposite to the noise signal,and cancels it at the noise reduction place,which has a good noise reduction effect at low frequencies.Active noise control systems include feed-forward systems,feedback systems,and hybrid structure control systems.The hybrid structure control system is a combination of the advantages of feed-forward and feedback systems.It has the characteristics of good noise reduction and wide application.This paper mainly researches active noise control algorithms based on hybrid structure control systems.Aiming at the problem that the existence of the secondary acoustic channel affects the noise reduction performance of the system,this paper conducts in-depth research on the Filter-x Least Mean Square(Fx LMS)algorithm.The offline transfer method is used to estimate the transfer function of the secondary acoustic channel.Simulation results show that the offline estimation can accurately estimate the transfer function of the secondary acoustic channel,thereby eliminating the effect of the secondary acoustic channel on the noise reduction performance of the system.Aiming at the problem that the noise reduction area of a single-channel active noise control system is too small to be suitable for application in practical application scenarios,this article conducts in-depth research on a multi-channel active noise control system.Multi-channel active noise control algorithm and single-channel active noise control algorithm are essentially the same.In order to reduce the calculation amount of the algorithm and simplify the complexity of the system,this paper optimizes the dual channel.Simulation results show that dual-channel active noise control has better noise reduction effect than single-channel active noise control.Aiming at the problem of coupling between the noise signals of the feedforward system and the feedback system in the traditional hybrid structure control system and the inaccuracy of the reference signal of the feedback system,this paper proposes a hybrid structure system based on error signal separation.It separates the error signals to solve the problem of coupling noise signals between the feedforward system and the feedback system,and at the same time solves the problem of inaccurate reference signals obtained by the feedback system,thereby improving the overall noise reduction performance of the system.The improved hybrid structure system in this paper,through simulation and comparison experiments,improves the overall noise reduction performance of the improved system.Finally,the Fx LMS algorithm is applied to the improved hybrid structure system in this paper,combined with the DSP chip to perform actual noise reduction in a semi-closed three-dimensional space.effect.