| The application of twin-propeller and twin-rudder in vessels has not been fully popularized.At present,it is mainly used in military ships and special ships,but less for civilian use.Because of its excellent characteristics has been recognized by the ship industry,scholars all over the world have carried out in-depth research on the performance of twin-propeller twin-rudder vessels.The twin-propeller twin-rudder vessel provides longitudinal thrust for the ship by two main propellers,the twin-rudder provides steering torque,and the vessel can also provide steering torque through the differential motion of the two main helices.Compared with single-propeller single-rudder vessel,twin-propeller twin-rudder vessel has the advantages of fast speed,good turning performance,strong maneuvers and good performance in shallow water.Therefore,twin-propeller twin-rudder vessels are more and more popular.The side thruster is the auxiliary propeller of the vessel,which can improve the control efficiency of the vessel.The use of side thruster can improve the vessel’s steering ability,so as to reduce the risk of collision,but also can increase the vessel’s positioning ability and berthing ability.It makes up for the problem that the rudder effect is almost lost when the speed is too low,and the vessel should be controlled by the auxiliary equipment.The combination of side thruster and twin-propeller twin-rudder greatly improves the performance of the vessel.The research object of this paper is a twin-propeller twin-rudder fire-fighting vessel with side thruster.Two main propellers can provide enough power for the fireboat,and the steering torque provided by the twin rudders makes it have good steering ability.Two main propellers with twin propellers can provide enough power for the fire-fighting vessel,and the steering torque provided by the twin rudders enables it to have a good steering ability.In addition,with the assistance of side thrusters,the overall performance of the vessel can be improved.If such a fire-fighting vessel is equipped with unmanned navigation,it can greatly improve the firefighting capability at sea.When unmanned,the fire-fighting vessel can be brought closer to the fire to extinguish the fire,or the fire-fighting vessel can be used as a lifeboat to enter the fire and rescue people.This paper mainly studies the control system of twin-propeller twin-rudder fire-fighting vessel.Firstly,the motion mathematical model of the twin-propeller twin-rudder fire-fighting vessel is established,and the hydrodynamic parameters of the twin-propeller twin-rudderfire-fighting vessel are calculated by using relevant software to simulate the motion of the ship.This paper also selects and builds hardware facilities for the control system of twin-propeller twin-rudder fireboat,and designs the corresponding upper computer software to collect data such as rudder angle,main engine speed,lateral push speed,control related switch amount and GPS signal.In addition,the upper computer software can be used to control the fire-fighting vessel,such as setting the rudder angle,the main engine speed.Then,the underactuated track tracking of two-propeller two-rudder vessel is studied without starting the side thruster,and the traditional line of sight based PID algorithm is used.Finally,under the condition of using the side thruster,the full-drive track tracking research is carried out on the twin-propeller twin-rudder fire-fighting vessel.Track tracking research is carried out in two conditions: with and without interference.When there is no external interference,dynamic sliding mode control is adopted.When there is interference,the disturbance observer is added on the basis of no interference,and an adaptive law is designed to estimate the error bounds of the disturbance observer. |
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