Optimized Design Of Sound Imager Based On Ring/Spiral Composite Array

As a monitoring method for machine fault diagnosis,noise signals have received more and more attention.Its advantages are non-contact detection,on-line monitoring and fault diagnosis.It can simultaneously separate and monitor the noise signals of multiple machines,and it is easy to install on site without interference from the vibration of the machine itself.These advantages determine the acoustics in some special applications.It may be the only feasible analytical detection method,which makes acoustics a research hotspot for mechanical fault location.Accurate positioning of noise sources is essential when acoustically locating mechanical sources of fault.The microphone array acoustic imaging equipment is used to locate the noise source.The research content mainly includes the research of array and localization algorithm.Therefore,this thesis focuses on the influence of the microphone array on the imaging performance of noise sources,and analyzes the characteristics of noise sources and the array of the microphone array.The intrinsic correlation of the design,the microphone array optimization design method based on noise source characteristics is proposed,which solves the problem that the universal microphone array cannot be optimally imaged,and improves the performance of noise source localization.In addition,this thesis is studied the multi-noise source localization algorithm,simulates the influence of noise source localization algorithm on noise source imaging recognition,and designs a set of microphone array acoustic imaging system,which works well in the identification of abnormal noise sources.The research content is as follows:Firstly,based on the analysis of the development history of the microphone array acoustic imaging equipment,the core content of this thesis is proposed:the design of the sound imaging array of a specific frequency microphone and the research of the microphone positioning algorithm,and its application to the noise source positioning..The array of microphone arrays has an important influence on the output of the beam type.The array of microphone with excellent performance should have smaller side lobes and narrower main lobes.Choosing a suitable array can obtain better recognition results.Through different arrays and simulation analysis of single sound source to multiple sound sources,a microphone array optimization design method is established.According to the noise frequency,an array for a specific noise source frequency is designed to better locate the noise source of a specific frequency.The traditional beamforming algorithm,controllable power response beamforming algorithm SRP,fast Fourier transform non-negative least squares beamforming algorithm FFTNNLS,fast soft threshold iterative algorithm FISTA and other noise source localization algorithms are studied.The advantages and disadvantages of the beamforming algorithm are compared and analyzed to obtain a better algorithm.According to the previous research contents and design methods,a set of 64-array microphone array acoustic imaging equipment,including software and hardware systems,is designed,and the sound source of specific noise source characteristics is located in the semi-anechoic chamber to obtain ideal results.At the experimental site,the noise source of a certain wheel noise source was identified,and the location of the noise source was found,which was well applied.