Research On Ship Motion Virtual Simulation Technology

Ship navigation in real world can consume large mount of financial resource and the physical resource. Moreover,it will sometimes lose one's life in dangerous situation.It is easy for the ship to upthrust shoal and collision accident when the ship drive in or out of harbour.The sunken wreck accident not only can lose national property but also cause shipman lose his life. Dealing with this problem ,virtual simulation is a extremely inexpensive and safe replace tool .Ship motion virtual simulation can really improve the training level of driver,and it is also an effective training tool of reducing all kinds of expenses.It adopts computer simulation technology,virtual reality technology, graphic image simulation technology and so on,and it makes the driver have factual feeling when he is driving the ship.It has the merits such as energy security,economy and training is not limited by time and environment and so on .Therefore, it is significant for both society and economical to develop a suit of ship motion simulation.At present,car driving training simulator,airplane simulator,tank simulator and virtual battlefield system have already developed widely and maturity,but there is very few simulator about ship motion,and most of them using fully physics or half physics(with the aid of actual hardware) simulation system. This system is the pure software simulation realization ships motion,it had achieved goal of simulation, saves the experimental cost and the safe .It Has also satisfied the human - machine real-time alternately, and can carry on the simulation experiment at any time, and it is a lso used as the basis for the later ships experiment and the collision examination.The technology of computer three-Dimension(3-D) simulation is a very important method . Using the technology of computer graphic image build 3D model or reappear the real environment.This can get the vivid simulation purpose. It makes user feel that he or she is in that environment.It can realize mutual interactive,and also supply to the user direct basis.In this paper,it mainly introduce simulation of ship in the harbor,Including building ship 3D model,terrain and physiognomy,human civil sight and so on..By calculating parameter of ship motion kinetics, we can get the correct results.The paper includes such contents as below.First Introduce. It mainly introduces background of external and internal simulation.At the same time give summarize of virtual reality technology.Second Mathematic model of ship motion. It mainly established four degrees-of-freedom mathematic model during the processing of ship motion.Based on the separated mathematic model, we can set up straight line move,rotation move,turning around motion,and portrait motion. When building up the mathematical model, the following factors have been considered: the forces and moments acted on ship's hull, propeller, rudder and interrelationships; the ship's movement on water surface and the rolling moment coupling.Third, Kinetics simulation research.Calculate mathematic model. It is the elementary of the above chapter. The paper applied the calculating method-the Runge-Kung method to calculate the equation of maneuvering mathematical model, and simulating calculated for the trials on the ship's maneuverability by matlab. Forth,The development environment of visual simulation and its key technology.It introduces the software environment of ship visual simulation system.The paper mainly uses three software:3D model building MultiGen Creator,3D real-time visual management software OpenGVS and Visual C++.The flow of 3D model using MultiGen Creator and all kinds of facilities of OpenGVS.It is the basis of ship simulation system.Then The reality of virtual simulation system. Reality of drive section has been brought forward.First,according to the task request we proposed all of objects'function that simulation needs.Then ,we introduced objects of the scene separately such as ship,light,fog and so on.The reality of ship manoeuvre is controlled by keyboard and joysticks; Special effect such as light and fog in the scene are designed by OpenGVS API; Flexible viewpoint is realized by callback function; through establishing path way other mobile in the scene can move.At last we can establish a complete ship virtual simulation system.The study of Simulation system in this paper can draw following production:1.Through building ship mathematic model can satisfied the simulation reality very well;2.3D ship model has been developed based on the true dimensition of ship.This can enhance the authenticity of the simulation;3.A suit of ship manipulation programme has been developed.Manipulator can control the ship by keyboard,joystick and other external equipment;4.Multiple camera and multiple viewport track technology can realize human-machine real-time interactive.This can fully embody the quality of real-time and alternation;5.High quality graphics picture.It can realize all kinds of special graphic effects such as air, sunlight, fog and so on.This can reinforce the truth;6.The virtual scene has real cubic feeling,it makes the driver feel far and near,depth and so on;7.Description of other moving object such as the flying seabird and other ship in the scene.The results of this thesis can put forward a certain theoretical method to simulate the ship's maneuverability in waves at same time.