Research On Rolling Bearing Fault Diagnosis Based On Optimal VMD Method

Rolling bearing as an important part of wind turbine,It can determines whether the wind power system run normally or not directly.In addition,the working condition of the bearing is very important to the safety of the equipment.Due to the poor installation environment of wind power equipment,the main bearing of wind turbine is prone to failure.In order to avoid the loss of life and property caused by serious accidents,it is meaningful to the monitoring and diagnosis of bearing working condition.In this paper,the main bearing of wind turbine is taken as the research object,and the vibration signal collected is analyzed and processed.First of all,this paper introduces the structure and general failure form of rolling bearing,and deduces several calculating methods of common fault characteristic frequency.This paper introduces some basic principles of empirical mode decomposition method,variational mode decomposition method and singular value decomposition method.Taking the constructed digital signal as an example,the method of taking value of K is given.Secondly,the ANSYS/LS-DYNA simulation model of rolling bearing under normal condition and outer ring fault state is compiled by command flow,the Y direction vibration acceleration signal is obtained by the display dynamics analysis of the simulation model by the post-processing software.Analysis of Vibration signals of simulated bearings under normal and Fault conditions using VMD method.Finally,a rolling bearing simulator is built to collect the vibration signals of the bearing under different power supply frequency and the fault of the outer ring.The vibration signals of outer ring faults are processed by EMD,VMD and the optimization of VMD method by singular value decomposition and kurtosis.The envelope spectrum is obtained by hilbert envelope demodulation,and the envelope spectrum of normal rolling bearing is compared and analyzed.The finite element simulation results show that the vibration signals obtained from the simulation model of rolling bearings under normal and outer ring faults are consistent with the actual motion conditions of rolling bearings.In the spectrum processed by VMD method,the fault characteristic information of the bearing can be reflected,and the simulation results are consistent with the experimental results,which verifies the feasibility of the dynamic simulation of the rolling bearing display.The comparison and analysis of the experimental results show that the optimized VMD method can extract the weak fault feature information accurately under different power supply frequency.In addition,the signal-to-noise ratio is greatly improved,and the processing result is superior to that of EMD and VMD.It is proved that optimized VMD is an effective signal processing method and can be applied to the fault diagnosis of rolling bearings.