Research On Speed Control Method For Marine Diesel Engine Based On Short-term Prediction Of Ship-pitching

Affected by sea waves, the ship exists six degrees of freedom movement when it sails on the sea. In the six degrees of freedom movement, pitching, rolling and heaving have the greatest impact on the ship’s safe navigation. The violent pitching can keep the propeller above water easily, in which situation it will lead to the marine diesel engine (MDE) coaster easily. Speed has bad influence on MDE safe operation. So if the imminent dangerous situation can be predicted accurately and adjusted, it will mean great significance to sailing safety. This paper mainly discusses the MDE speed control method based on the ship pitching short-term prediction.Firstly, according to the relationship between the wave and pitching, the ship pitching model is established. Combined with time series AR model method, the parameters of pitching model are estimated and then the ship pitching short-term prediction model is established. The simulation results prove the accuracy of prediction model.Secondly, through the research on the operational principle and characteristics of MDE, the MDE model is established.The MDE speed control methods are studied.. Finally, the MDE speed control methods based on the ship pitching short-term prediction is studied. Through the identification of the ship pitching prediction results and controlling the MDE speed in advance when the forecasting value exceeds the set value, coaster caused by the propeller suddenly appearing out of the water is avoided. The simulation results show the feasibility and the effectiveness of the control method. This method can ensure the safe operation of the MDE in adverse sea conditions and avoid the situation of propeller racing. Then the ship is more secure and reliable when sails on the sea.