The Prediction of Nonlinear Ship Motion Based on Multi-Varible Grey Model MGM(1,n)

The six-degree-freedom motion of ship is a complex nonlinear system. The forecasting for nonlinear ship motion is hard to achieve for the mutual couplings between freedoms, and there is no proper method to deal with this work right now. The multivarible grey model MGM(1,n) is a system model characterizing the mutual influences of the parameters by differential equations, which can simulate and predict the trend of parameters effectively without much prior information. In this paper, a method is proposed to do nonlinear prediction for ship motion based on MGM(1,n). The model is built to the pitch, heave and wave data after doing range transformation which makes the data fit for the model. Finally, the prediction of coupled pitch-heave motion is got from numerical experiment.