Research On Sound Source Identification And Sound Field Separation Method For Single Holographic Surface

Sound source recognition is the premise of automobile noise control and improving NVH performance.Near-field sound holography is a sound source recognition technology that uses array measurement technology and reconstructs 3d sound field.In general,there are multiple coherent noise sources in the actual sound field environment.Based on this,this paper mainly studies the sound source recognition method and sound field separation methods.Firstly,The compression sensing method is used to identify the unknown location.The theoretical framework of compressed sensing is discussed from three aspects:sparse representation of original signal,design of observation matrix and reconstruction method.The source intensity density is estimated by reconstructed signal,and then the location of sound source is identified.Two reconstruction methods,orthogonal matching tracing method and convex optimization method,,are introduced,and their numerical simulation is carried out.The results shoe that the two methods can identify the coherent sound source.The larger the holographic array is,the lower the minimum frequency of the accurate identification of sound source is.The coherent sound source spacing also has a certain influence on the accuracy of sound source recognition.Secondly,in order to reduce the measuring points of holographic plane,a method based on vibration velocity of separated particles.Based on wave superposition near-field sound holography,the separation formula of sound field is deduced according to the principle of error between the theoretical value and the measured value,The regularization methods and regularization parameters are introduced for the ill-posed acoustic inverse problem;The equivalent sphere radius,the equivalent numberof sources and the holographic surface which affect the separation accuracy are analyzed by numerical simulations.The results show that this method can effectively separate coherent sound sources.When the radius of the equivalent source sphere is smaller,the separation error is smaller.Comparing with the method of measuring partical vibration velocity based on sound pressure,it is found that the vibration velocity of particle separated by sound field separation method based on vibration velocity measurement is more accurate.Finally,the single holographic surface sound source recognition and sound field separation are verified by experiments.In the experiment,two acoustics are used as sound sources,and a wheel array composed of 18 sensors is used to measure the sound field,and using Matlab to deal with the experimental data,the compressive sensing sound source recognition method based on orthogonal matching tracking combine with convex optimization can identify a single sound and two coherent sound.The single-sided sound field separation method is used to separate the velocity of the particle on the holographic surface,and compared with the theoretical separation velocity,the error is small between them.Reconstruction of the target source sound field,showing that compressed sensing sound source identification method and sound field separation method are correct and effective.