Design Of Suspension Frame Modal Analysis System Based On Blind Source Separation

With the rapid development of China’s economy and the increasing movement of people,the ultra-high speed low vacuum tube magnetic levitation transportation system has emerged.In order to optimize the design of the suspension frame structure and detect the health status of the suspension frame,it is necessary to identify the modal parameters of the suspension frame structure of the magnetic levitation transportation system.The operational modal analysis method is to apply natural excitation to the system under the operating condition of the equipment and solve the modal parameters of the large structure by measuring the output response of the system.This method does not require artificial excitation of the structure,does not affect the normal operation of the structure,and the solved modal parameters are more consistent with the actual operating conditions.However,the existing modal parameter identification methods have problems in practical application,such as high difficulty in getting started,difficulty in identifying false modalities,and large human influence factors.Based on this,this thesis designs a blind source separation-based modal analysis system for the suspension frame.By collecting the vibration data of the suspension frame structure during the test of the magnetic levitation transportation system,the vibration data is pre-processed by the vibration data processing and analysis software,and the modal parameters of the suspension frame structure are solved by the blind source separation technique.The main contents of this thesis are as follows:In terms of hardware design,a four-channel vibration data collector is designed to collect the vibration data of the suspension frame in the test state of the magnetic levitation transportation system,and the data conditioning circuit,data sampling circuit,FPGA control circuit,data storage circuit and power conversion circuit are designed;the AD timing control,FIFO module design and SD card storage function are completed;the PCB board drawing is carried out,and the vibration data The PCB board was drawn,and the overall performance of the vibration data collector was verified,and the acquisition of vibration data was realized.In terms of software design,the Lab VIEW-based vibration data processing and analysis software of the suspension frame was developed to display waveforms and process the vibration data collected by the vibration data collector,and the design methods of each data processing module were elaborated.In terms of modal analysis,a single suspension model was built using ANSYS software based on the structure of the suspension frame in the ultra-high speed low vacuum tube magnetic levitation transportation system;the test environment was analyzed,and the necessity of vibration signal denoising was derived;the modal analysis process based on blind source separation was designed,and the Fast ICA denoising algorithm and SOBI modal parameter identification algorithm were written;the MATLAB software was used to verify The feasibility of the blind source separation algorithm for modal analysis was verified by using MATLAB software,and the necessity of denoising for modal analysis was verified.