Research On Steering Gear Model And Track-keeping Autopilot System Of Ship

With the increasing in maritime transport and port, the request of security and economy of navigation is becoming higher. The requirement of course control and track-keeping control is getting higher and higher. The existing control system of ship that performance and structure have to be further raised, is mainly focus on the course or indirect track control. So, considering each parts of the ship's control system(such as Rudder Servo System), design high-precision ship control system has become an important research topic. Therefore, The main task of this topic is to design track-keeping system of the ship in two ways and two control algorithms, based on the actual model of hydraulic steering gear and four-freedom model of ship, considering environmental interference forces the ship suffered.First, establish the four-freedom mathematical model of ship based on MMG (Manoeuvring Mathematical Model Group) and environmental interference forces(wind wave flow) model. Based on spectral analysis, simulate the changing wind and irregular wave .To be the main executive part of the ship's motion control system- the Hydraulic Steering Gear System, described the calculation method of the rudder force and torque in detail in the interference of the ship and propeller. Consider each part of steering gear and the control method of system, under the certain conditions, establish the dynamic mathematical model of a particular model for hydraulic steering gear system using the Simulink toolbox, Consider the steering servo system of the rudder angle of the dynamic behavior of the closed-loop.The ship's track-keeping control is one of the most important contents, which mainly includes two control ways of track-keeping, the calculation method of track error, the strategy on turning track passage. Finally, For the indirect method and direct method, designs two ships track-keeping controller that use a switching-type fuzzy-PID and PID algorithms. Research and simulation of the ship track under the different sea condition, Adding the control strategy on way-point.The control system designed in this paper provide a certain reference to the large surface ships for navigation's safety and economy. Adding the control strategy in the turning passage further improve the accuracy of track. Hydraulic steering gear, as a subsystem of ship motion control system, Building mathematical model of hydraulic steering gear and considering its dynamic behavior provide the condition for research on the precise of the track-keeping system.