Study On Coupling Faults Of Rotary Machinery Diagnosis Method Based On HHT

Rotating machinery is the key equipment in industrial field and has been widely used in the departments of electric power, petroleum, metallurgy, and aviation. But due to the poor manufacturing and assembly or because the system in high speed and high load condition, it is easy to occur the problem of rotor imbalance and misalignment, if has not been timely diagnosed, it will cause secondary faults such as rubbing and basic loose, cause fault of mutual coupling, which will cause significant influence to the normal operation of the machine. And once the system failed, often is not in one form of fault, but in the form of mutual coupling fault occurs. This kind of situation is more complicated than relatively single fault vibration mechanism, and the diagnosis is more difficult. In the paper rotating machinery system is the research object, considering the complexity of the mechanical coupling faults, focusing on fault diagnosis of rotating machinery coupling method based on HHT, and through the establishment of fault model to study the fault features, a new method has been put forward to solute the problem occurred in HHT envelope fitting, and has been applied to the coupling fault diagnosis successfully.In the envelope fitting will appear overshoot/undershoot and endpoint effect, three Hermite interpolation method is used to replace the original three samples, to overcome the overshoot/undershoot phenomenon. For the endpoint effect, the slope to optimize the continuation and combined inhibition of window function method has been used to make the intrinsic mode function of decomposed more close to the real value, improve the accuracy of decomposition of HHT method.For rotating machinery fault diagnosis, fault coupling rotor-bearing system model has been established. The model not only contained wrong and rubbing fault, but also considered the influence of nonlinear oil film force. Variable step size fourth-order runge-kutta method has been used to calculate the numerical solution of the system, derived signal with fault analysis features.An improved HHT coupled and Fast ICA combination of rotating machinery fault diagnosis method has been put forward. The method use improved HHT to decomposition of fault signal obtained by the model to get the fund, and then use the Hilbert transform to deal with the IMF, decompensate the Fast ICA, spectral analysis is used to obtain two fault feature vectors of misalignment and coupling faults rubbing for effectively and accurately couple fault diagnosis.Combining HHT and higher-order cumulate, form a new method for fault diagnosis of rotating mechanical coupling. Use the new diagnosis method to analyze crack- rubbing fault diagnosis, Get cracking, rubbing fault coupling fault feature vector. Compared to the Traditional diagnostic methods, the new method indicate the characteristics of fault signal more intuitive and exact, and diagnose the coupling failure more effective and accurate.