The mathematical model of ship maneuvering is the core of the ship maneuvering off-line simulation system, it establishes three degrees of freedom motion control equation of the rigid body dynamics , in which the ship as a rigid body. Using MMG (Ship Maneuvering Mathematical Model Group) detached method, it considers the role of force and torque as well as the three mutual influences of hull, propeller and rudder respectively, than it applies runge-kutta method to solve differential equations and combine them with matlab programming languages. According to the rotation test and Z-style test of the kiloton ship, the ship maneuvering offline simulation system is proved to be correct and reliable. So we use this system to simulate the movement of ship passing through the continuous meandering bend in different situations. Then, we analyze rudder angle, drift angle and channel width of ship traveling through the continuous meandering bend, and we can find that when the length of transition section is less than 160m, the rudder angle and drift angle which ship is sailing across the after bend are obviously bigger than that of front bend; when the length of transition section increase a certain length, navigational parameter of front bend and after bend are basically the same, however, when it continues to increase, navigational parameter of front bend and after bend will not change and it will remain steady. Then, we define that the length is the critical navigation length of transition section. At the same time, we also can find that the minimum navigable length of transition section increase with the central angle of bend increase, and it will decrease with bending radius increase. When the central angle of bend is more than or equal to ninety degrees, the standard formula results must be certain modified.
Digital Block Mathematical Model for the Joint Hardware and Software/firmware Simulation System
