Research On Lift Model And Controller Of Zero-Speed Fin Stabilizer

In recent years, people pay more and more attention to and make increasing demands of the roll stability of ships, not only sailing but also anchoring and drifting, especially large motor yachts, warships carrying weapons, research vessels and other vessels for special operations at sea.Anti-roll tank system is the only choice for ship to reduce roll under zero speed, but the effect is not very good, it can only reach to 50% under all conditions. Fin stabilizer can reduce the most roll of the ship under high speed, but it hardly reduces the roll of the ship under low speed or zero speed. The ship which needs to reduce the roll under all kinds of ship speed has to equip two pair of anti-roll systems: fin stabilizer and anti-roll system to meet the need. The advantage is obvious, but it means that there are two systems to design and maintain. Two systems not only occupy more inner space of the ship but also increase the cost. If fin stabilizer can reduce the roll of the ship under low speed and zero speed, it means that there is only one pair of system to maintain and doesn't need more inner space of the ship. So it is important to research and analyze the lift which generates by the movement of the fin and build a lift model of the fin.According to the special working mode of zero-speed fin stabilizer, the lift force on fin is analyzed based on potential theory and vortex counterforce theory. Then lift model is set up based on analysis. To compute the lift on fins with Fluent when the angle of fin changes with sinusoidal orderliness and modify the lift model using data from Fluent.To design a PID controller based on neuron network for the nonlinear and uncertain system. Do simulation under several ocean wave disturbance. Compare the results between neuron PID controller and traditional PID controller. The results show that system with neuron PID controller has a strong adaptability for the nonlinear and uncertain system. System under neuron PID controller use less energy and it is very important for the design of the servo.