Wenhao Bi / Beijing University of Chemical Technology
Mei Li / Beijing University of Chemical Technology
Yanfei Zuo / Beijing University of Chemical Technology
Aiming at the problems of insufficient real-time monitoring of the dynamic characteristics of rotating machinery under multiple working conditions and high data acquisition costs, A twin model construction method for unbalanced vibration in rotor systems based on random forests is proposed in this paper to achieve rapid prediction of the unbalance or vibration response. Based on the finite element dynamic model, the characteristic data are obtained by applying unbalanced excitation through harmonic response analysis. On the basis of considering the dynamic characteristics of the rotor system, the key node features are extracted based on K-means clustering sampling. According to the requirements of different application scenarios, a three-level prediction twin model is constructed based on the dynamic characteristics of key nodes after order reduction: Model Ⅰ for predicting unbalance, Model Ⅱ for predicting both unbalance and rotational frequency simultaneously, and Model Ⅲ for predicting the frequency response function covering the entire frequency band. Taking the finite element model of a certain rotor system as an example for verification, the results show that the root mean square error (RMSE) of Model Ⅰ in the unbalance prediction is 0.1726 g·m, and the mean absolute error (MAE) is 0.15 g·m. In the rotational frequency prediction of Model Ⅱ, the error does not exceed 0.9 Hz. The RMSE of the unbalance prediction is 0.1504 g·m, and the MAE is 0.116 g·m. In the frequency response function prediction of Model Ⅲ, the Pearson correlation coefficients of each measurement point are all higher than 0.98. The validation results demonstrate that the proposed method offers excellent prediction accuracy and practical engineering value. Real-time inversion of unbalance, rapid and accurate prediction of rotational speed and unbalance in the keyless phase, and overall dynamic balance within the working rotational speed range can be achieved through this method.