Online prediction of hydro-pneumatic tensioner system of floating platform under internal waves

To address the issue of low accuracy in the current motion response prediction model of the floating platform tensioner system, this paper proposes an online prediction method that integrates Empirical Mode Decomposition (EMD), Kernel Principal Component Analysis (KPCA), and Long Short-Term Memory (LSTM). The EMD technique is employed to decompose the sequence of environmental factors, reducing their non-stationarity. Subsequently, KPCA is used to extract key influencing factors and reduce input dimensionality. Finally, LSTM neural networks are applied to capture long-term dependencies in features and make accurate predictions. By validating the model using motion response data from the tensioner platform device under two scenarios with and without internal waves, it is compared against other models. The results show that the EMD-KPCA-LSTM model has high prediction accuracy in both scenarios. In particular, compared with the Convolutional Neural Network (CNN) model, the mean Root Mean Square Error (RMSE), Mean Absolute Error (MAE) and Mean Absolute Percentage Error (MAPE) of the displacement and tension of the system decreased by 52.97%, 55.14%, 56.31%, 68.97%, 71.02% 57.60%, respectively, and R-square (R²) increased by 7.14% and 12.37%. In summary, the model has a good ability for data fitting and high prediction accuracy and has important practical value.