Research On The Sub System Of Tug In Ship Handling Simulator

Presently, large ship handling simulator has been used widely in seafarers training, sea route design, project argumentation and simulating test, and delightful result has been obtained. As the development of vessels' becoming larger and larger even extremely larger, manipulating vessels becomes difficult more and more, such as: entering or leaving port, berthing or unberthing etc. Under this condition, tug's assistance to large ships has been become an important means to help large ship enter or leave port. From the point of view of improving large ship handling simulator, it's necessary to adding the tug model to ship handling simulator as an own ship that can simulate the manipulability between tug and large ship. It can provide real effects of tug's assistance to ship officer but also provide a vivid manipulating environment to tug officer.According to the request for application field of the ship handling simulator with 3-D scene system in the STCW/78/95, we know that ship handling simulator should provide manipulating environment as vivid and perfect as possible to ship officers.Here, ships manoeuvring mathematical model and 3-D scene system are the most important parts. Stand or fall of scene and nicety or not of the ship manoeuvring mathematical model are the key of the whole ship handling simulator.This paper did some researches on characteristics of scene system, manipulating environment and tug mathematical model in tug simulator. According to the MMG's separated modeling theory, an integrated and accurate mathematical model is established. During the course of modeling, constitution of coordinate system, calculation of ship hull force, calculation of water resistance, calculation of wake fraction of propeller and thrust deduction factor, calculation of thrust and torque coefficient of ducted propeller, calculation of thrust, transverse force and torque of twin-stern propeller, mathematical model of main engine have been talked about in detail. Then, a 3 DOF tug manoeuvring mathematical model is established which can be applied to the large ship handling simulator. Furthermore, this paper does some elementary researches on mathematical model of tug's pushing and pulling and provides a simple mathematical model.Based on the established mathematical model, the author establishes a real 3D geometrical model of tug ship with 3D modeling software, develops a 3D engine of scene system with OpenGVS, adds the tug as a ownship to ship handling simulator and displays the tug model in the scene system. In the end, the author uses catenary as mathematical model of mooring lines, transforms centenary to 3-D model with geometrical transform, real-time displays the mooring lines in the scene system of ship handling simulator according to the coordinate information of length of mooring lines, mooring point and mooring stakes.