Research On Fault Diagnosis Method Of Rotating Machinery Bearing With Variable Speed

Rolling bearing is one of the most important parts of rotating machinery,and it is also one of the mechanical parts which are easy to be damaged.When the traditional Fourier transform method is used to deal with the vibration signal under the condition of variable speed,it will produce a serious "frequency ambiguity" phenomenon.The order analysis is an effective method to deal with the variable speed signal.It is very important to solve the problem of order analysis under the condition of no tachometer.Firstly,the vibration signal of rolling bearing is studied under the condition of variable speed,and using the numerical differential methodthe calculates speed curve.Studying the application of the anti-rank mixed filtering technique determines resampling order.The validity and accuracy of COT(Computed Order Tracking)technology is proved by the simulation signal.Accurate instantaneous speed calculation is the precondition for the development of non-speed tracking,in order to improve the precision of instantaneous speed,a new method based on wavelet entropy to optimize the complex Morlet wavelet time-frequency distribution is proposed.Using the minimum wavelet entropy optimize scale parameter to improve time-frequency resolution.The simulation results show that the time-frequency resolution can be improved greatly.The advantages and disadvantages of the local peak search algorithm and Viterbi algorithm are compared with the simulation signals of the single order and the adjacent order.The results show that the Viterbi algorithm performs better in terms of accuracy,adaptability and noise resistance.Based on the rolling bearing fault diagnosis system,the algorithm is applied to the fault diagnosis of rolling bearing with variable speed.The experimental results show that the proposed algorithm can effectively diagnose the rolling bearing faults under variable speed conditions.The research results provide a new way to solve the problem of bearing faultdiagnosis under variable speed conditions,which has important theoretical and practical value.