Mathematical Model Of Towing Operation With Four Degrees Of Freedom In Tug Simulator

As a kind of auxiliary means,tug plays a very important role in towing and assisting large vessels against unberthing.In January 2011,Det Norske Veritas is mentioned,A-class navigation simulator has at least one tug model to simulate tug’s pushing,towing,reset and escort role.Establishing towing mathematical model is the necessary preparation for the tug operation mathematical model for further study,also is an important part of tug simulator research.For this purpose,the following research work is done in this paper:Firstly,the four degree of freedom motion mathematical model of Z-propeller tug and large-scale loaded liquefied natural gas ship was established based on the idea of MMG model.At the same time,the ship cycle test was done by using the established mathematical model.Comparing the experimental data with the relevant real ship data,the rationality of the model is verified.Secondly,The establishment of wind and current disturbance model.The wind force and torque mathematical model and current interference model is established.Then the Z-propeller tug and large-scale loaded liquefied natural gas ship with tugboat maneuvering motion simulation forecast was done.Thirdly,the towline model was established based on the catenary model.Through the calculation of the towline tension,the real-time solution of count of the towline tension was joined the towing operation mathematical model.In addition,the use of established Z-propeller tug and towline model towing a ship unpowered barges for direct stability test to verify the correctness of the models.Fourthly,the overall towing four degree of freedom mathematical model was established.And the simulation experiment on the overall model of programming was done using VS 2013.Fifthly,the simulation of operation of tug towing under different conditions based on the simulation platform.And the simulation results will be more close to the actual situation by adding environmental factors.Through research of towing operation mathematical model,a series of in line with the actual situation of the simulation results,and further improve the tug simulator in towing simulation part.At the same time,this paper is to provide a theoretical basis for towing ship operation.