Abstract:  The variational mode decomposition characteristic energy reconstruction (VMD) method has a problem of low accuracy in fault realization. Aiming at this problem, a fault diagnosis method of piston pump slipper wear based on variational mode decomposition (VMD) and multi-scale entropy was proposed. Firstly, the energy allowance of original signal was obtained by VMD decomposition, a VMD-MDE(multiscale distribute entropy)method based on characteristics of energy ratio (FER) was designed. Taking the fault diagnosis of the piston pump as the research object, the condition of the piston pump under the normal condition and the slipper end wear of 0.1mm, 0.2mm and 0.3mm was analyzed in turn. The simulation results show that the randomness and complexity of the coarsegrained sequence decrease obviously with the increase of time scale. After the degree of failure increases, a more regular change process is formed. Comparing with DE, MSE and MFE, the calculation speed is faster and the separation effect is better. The training time of ELM compared to SVM is reduced by 12.5%, and the test accuracy is increased by 17%. The efficiency of fault diagnosis is improved. Comparing with other methods, the proposed method can obtain faster classification rate and higher accuracy when diagnosing slipper wear fault of the plunger pump.

Key words:  plunger pump; wear vibration; signal extraction;variational mode decomposition characteristic energy reconstruction (VMD); characteristics of energy ratio (FER);multiscale distribute entropy(MDE)

QU Quan-peng, QU Hai-jun, ZHANG Qiang. Fault diagnosis of plunger pump wear based on VMD-MDE method［J］.Journal of Mechanical & Electrical Engineering, 2021,38(9):1202-1206.