Research On The Heading Control With Special Manipulation Devices For An Air Cushion Vehicle

Air Cushion Vehicle is a high performance ship, its structure is different from other vessels, its weight is borne by the air-cushion below the vessel, and the vessel is isolated from the surface or the ground by the air-cushion. It adopts air propeller and has amphibious nature. Air Cushion Vehicle has different manipulation control characteristics from other vehicles because of its own characteristic. As it has no underwater devices, it can not generate rotary force by the underwater device as other vessels, and it also can not rotate by the lift produced by the aileron as the aircraft.Hovercraft produces the rotary force by the air rudder, as the ship is floating on the water, the water resistance and the yaw resistance is very small, then the ship can easily drift when steering, the heading is also very easy to be changed, while the track has not really circumgyrated. In the crosswind, the hovercraft can easily be missed, drifted, heel etc, coupled with the high speed of the hovercraft, the hovercraft is difficult to control. In this time we can start the specific control devices of the hovercraft to manipulate it. In this paper, we studied the special control device (executive institution) of the hovercraft in the hovercraft heading control. The special control devices of the hovercraft including rotating nozzle, propeller, lateral throttle and so on. We can control the heading and gyration by these executive institutions.We take the hovercraft as the research object in this paper. Firstly, we establish the models for each parts of the hovercraft, such as aerodynamic model, hydrodynamic model, propeller thrust model, air rudder model, lateral throttle model and the rotating nozzle model. Then we get the motion equation of the hovercraft using the dynamic theorem of rigid body under the fixed coordinate system, after that, we convert it to the moving coordinate system and we finished the four DOF mathematical model of the hovercraft. In order to test the validity of the model, we imitated the real test for the hovercraft. Secondly, we introduced the basic theory of genetic algorithm and the theory to optimize the parameters of PID controller based on genetic algorithm, and designed adaptive online genetic algorithm tuning PID controller according to the purpose of the paper. Finally, we designed PID control and PID controller based on genetic algorithm for each executive institution to control the heading of the hovercraft. And we do the simulation with wind and without wind in order to test the effectiveness of the control devices and the superiority of the algorithm.