Virtual Reality Simulation For Large Ship's Motion Attitude

As the instant development of ocean carrying trade and the navy's requirement of large warships,with the progress of shipbuilding technology, "Large ship" is becoming a trend and the scale and tonnage of ship are increasing day after day.The navigation control and the attitude control of large ships bring all-important influence to the sailing security and weapon's service precision.This thesis,taking the large ships as the object,establishes the mathematical model of ship motion with four degrees of freedom(4-DoF),researches on the navigation control rule and achieves the dynamic show of ship motion attitude by the virtual reality technology.Firstly,in this thesis,the mathematical model of ship motion with 4-DoF is established based on the MMG separation formula.When building up the mathematical model,the following factors are discussed:the forces and moments act on ship's hull,propeller,rudder and interrelationships.The ship's movement on water surface and the heeling coupling,and the interference forces and moments of winds and waves are fully considered.Then,the thesis takes one certain large containership for example,simulates the ship's maneuverability both in the still water and in the winds and waves.The results are analyzed and the motion rules are summarized.Secondly,the traditional PID control and robust PID control are researched, the parameters of the two autopilots are calculated and the course control simulation is accomplished.The results show that the robust PID control has better anti-jamming performance than the traditional PID control.Finally,the virtual reality technology is used to visualize ship motion and the ship motion attitude is simulated intuitively through creating the virtual environmental scene,building ship 3D model and using the control model.The research of this thesis is mainly to large ships,and a lot of related data at home and abroad is consulted.The simulation results verify the correctness of the relevant theories.It can provide the reference for large ships' navigation control.