Research On The Motion Prediction And Constraint Control Method For Safe Navigation Of Hovercraft

With the progress of science and technology,land resources have been unable to meet human needs.The sea itself is a treasure trove of abundant resources,which has attracted the attention of mankind.With the continuous exploration of the sea,the capability of the ordinary ship has not been able to undertake all the exploration projects,so the high performance ship is emerged.As a kind of high performance ship,the hovercraft has higher speed of navigation,transportation capacity and environmental adaptability.Though the hovercraft is more suitable than the general ship,it is more susceptible to wind and wave interference due to small water resistance.The hovercraft cannot do rotary motion by the centripetal force generated by the heeling.Because of hovercraft not have underwater rotating equipment that cause its rotary radius increases.The complicated and changeable sea conditions and the high speed of the navigation will make the driver more difficult to control.It is easy to cause side slip,tail and boat capsizing hazard.Therefore,the safe navigation of hovercraft has become an important research area.The research object of this paper is the hovercraft.The specific research process is as follows:Firstly,the fixed and body coordinate system are established.Through a certain type of hovercraft experimental data and actuator parameters,modeling modules of the hovercraft.The model mainly includes the dynamic model of the hovercraft and the environment model.The dynamic model include the hydrodynamic model,the aerodynamic model,the control surface model and the air cushion force model.By combining the mathematical models of each part,a complete six-degree model of hovercraft is established,and the rationality of the model is verified by simulation.Secondly,because the hovercraft is subject to the noise of its own system and external interference,the motion data of the hovercraft sensor contains noise and abnormal value.Therefore,the data preprocessing method is used to eliminate the wild values,and the modified wavelet threshold function is used to filter the noise and smooth the data.The validity of this method is verified by using the method to smoothing the measured maritime data.Then,use the integrated prediction method to predict the motion parameters of hovercraft.This paper adopts the integrated prediction method combining grey system theory and Elman neural network.The simulation results show that this method can effective predict the motion parameters of the hovercraft.Finally,according to the safety navigation problems of the hovercraft,the security clearance of the hovercraft parameters during the navigation process is established.The hovercraft model is simplified and the sliding mode controller is designed based on the model.The controller is combined with the integrated prediction model to realize the control of the air cushion ship and improve its safe navigation.