Research On Power Spectral Density Reproduction Of Random Vibration Of Vehicle Material Friction And Noise Test Bench

During the driving process of the vehicle,due to the random vibration excitation of the road surface,the materials in the vehicle are rubbed against each other,resulting in abnormal noise.At present,the research on the friction noise test of automotive materials only uses the linear motion friction test to obtain the Risk Priority Number of the friction noise between the two materials,so as to predict whether the friction noise will occur in the material,but cannot simulate the material in the friction noise.The abnormal friction noise caused by the complex relative motion on the actual road;in addition,due to the long test period of the real vehicle and the difficulty of measurement,the relevant test bench is usually built in the laboratory to accurately reproduce the random vibration of the real road surface and conduct random vibration tests.In order to accurately reproduce the random vibration of the road surface,this paper develops a test bench for friction and abnormal noise of vehicle materials and the corresponding experimental software,and studies the random vibration power spectral density reproduction control method.The main research contents include:(1)Analyze the friction random vibration principle,random vibration test characteristics and test methods of vehicle materials,and complete the design of the friction and abnormal noise test platform for vehicle materials on this basis,mainly including the hardware selection of the test platform control system and the electrical schematic diagram of the system Design and test platform mechanical structure design.(2)According to the realization principle of random vibration power spectral density reproduction,a random vibration power spectral density reproduction control algorithm based on error iterative correction is proposed,and each step of the algorithm is studied,including the estimation of the system frequency response function and the calculation of the system impedance function.,system drive spectrum correction,system time domain drive signal generation and system response acceleration spectrum estimation;some steps of the algorithm are tested to verify its rationality and feasibility.(3)Considering the accuracy of power spectral density reproduction,a random vibration power spectral power spectral density reproduction control method based on adaptive inverse control is proposed.The principle of the adaptive inverse control model and the adaptive LMS algorithm are analyzed and optimized,and the frequency domain-X filtering adaptive inverse control method is proposed to realize the real-time correction of the frequency response function of the system.In order to ensure the convergence speed of the system,a Based on the power spectral density reproduction method of adaptive inverse control with variable step size,the frequency-X filtering adaptive inverse control algorithm with variable step size is studied,and the adjustment criterion of its step size is analyzed.The realization process is analyzed,and two evaluation indexes of power spectral density reproduction accuracy are proposed.(4)Based on the above power spectral density reproduction algorithm,the software design of the random vibration vehicle material friction and abnormal noise experimental platform is carried out,and the test results are analyzed.By analyzing the random vibration test process of the material friction and abnormal noise test bench,the random vibration control system software of the vehicle material friction and abnormal noise test bench is developed,including the upper computer man-machine interface and the lower computer control program,and the design of the test platform software is completed;Based on the test platform built above,two random vibration power spectral density reproduction control methods are tested and verified,and the accuracy and rationality of the adaptive inverse control method based on frequency domain-X filtering are confirmed.