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Fault Diagnosis Based on the Optimization of Characteristic Parameters and Neural Networks of Gearboxes

Gearboxes are the most commonly used transmission components in heavy equipment such as helicopters, shearers, and ships. The failure rate of gearboxes is high, and the characteristic signals under faulty conditions tend to be extremely weak and are often overwhelmed by strong noise. Thus, extracting sensitive characteristic parameters is difficult. In order to optimize the characteristic parameters of gearboxes and improve diagnosis efficiency, this study proposed a method for fault diagnosis of gearboxes that combines empirical mode decomposition (EMD) with rough sets and neural networks. First, the principle of EMD was explored. The indicators for measuring characteristic parameters were identified to compare the feature set composed of energy values with those comprising approximate entropy parameters. Second, the conditional attribute reduction technique for rough sets was investigated. An algorithm for attribute reduction based on conditional equivalence classification was put forward for parameter optimization. Then, a neural network was employed to identify the feature sets before and after the attribute reduction. Results show that the energy characteristic set is the most sensitive to failures. The attribute reduction technique reduces the characteristic parameters from 6 to 4, thereby effectively lowering the input vectors of the neural network. The training time is also decreased from 1.024 s to 0.351 s, obviously promoting the efficiency of fault diagnosis. The study provides references for improving the performance of online real-time fault diagnosis.