Research On Mechanical Fault Diagnosis Based On Microphone Array

Microphone arrays are often used for sound source location detection.The identification of the noise source is based on the sound source localization algorithm of the microphone array.The sound source localization algorithm is divided into three parts.One is based on the beamforming method,the other is based on the high-resolution spectral estimation method,and the third is based on the sound delay difference(TDOA)method.In this thesis,the source of mechanical fault noise is located based on the beamforming method,in order to achieve the purpose of mechanical fault detection.The mechanical platform fault location in the near-field range studied in this paper.Therefore,in this thesis,the theory of near-field acoustic wave propagation model and microphone localization is deduced and studied.A set of microphone array acquisition system is built and applied to fault detection.A method of removing coupling interference is also proposed and tested.Therefore,based on the near-field spherical wave model,the theory of microphone array positioning noise source is studied.A set of microphone array acquisition system is built and applied to fault detection.The research content of this thesis consists of the following parts:The first chapter introduces the development process of acoustic technology applied to fault detection at home and abroad.,and proposes the purpose and significance of studying the relationship between near-field noise source location and fault detection of microphone array.The second chapter introduces the concept of noise source and the basic theory of audio signal processing.The near-field signal processing model is studied.The near-field array response matrix is derived based on the near-field spherical wave model,and the steering vector of the array is obtained.The microphone array structure analyzes the linear array,the circular array and the spiral array respectively,and the selected spiral array is used for the final scheme of the subject.The third chapter studies the basic theory of sound source localization.The fourth chapter uses Matlab to simulate single-source,dual-source and multisource algorithms,and simulates fault sources with characteristic frequencies in different frequency noise sources.The fifth chapter builds the microphone array of the subject.After the signal is collected,the signal is processed to obtain the fault characteristic frequency,and then the beamforming algorithm is used to locate the fault.The sixth chapter,the coupling interference is proposed,and the decoupled interference algorithm is studied and verified.The seventh chapter summarizes the topics,discusses the advantages and disadvantages of the topics,and points out the ways in which the topics can be improved.