Study On The Control Method Of The Air Cushion Pressure Of The ACV In The Wave

As an amphibious vehicle, Air Cushion Vehicle (ACV) can be used not only on the surface of the water, but also on some flat surface of the land. The formation of an air cushion layer between water and an ACV when traveling on the water surface will greatly reduce the water resistance, which has led to a better mobility and speed ability compared with other ships. Therefore in recent years, it has been highly valued in the military and civilia.However, because of the cushion system, the air dynamics model of an ACV is quite different fromother ships. During operation, the sideslip caused by terrible stability will easily lead the ACV into a dangerous state.Due to the impact of the wave, the vertical join forces have changed because of the air chamber drainage. The excessive vertical acceleration is the major cause for not only the terrible ride feeling,but also damage of machine,pipeline, seats and other equipment and devices, which will result in the increasing safety hazard of a traveling ACV. Hence the stability of the cushion pressure is extremely important for the operation of the ship.In this paper, the problem of instability of air cushion pressure will be solved according to the following steps:Firstly, a six degree of freedom motion mathematical model of ACV is established in this paper. And the conversion between the fixed coordinate system and the moving coordinate system is carried out. On this basis,the air power, water power, air rudder, propeller and other models of the ACV are modeled. The correctness of the model is verified through the simulation experiment of forward motion and rotary motion.Secondly, a mathematical model for the ACV system is established. The aerial drainage capacity equation of each gas chamber and one between chambers are also established.After the establishment of the pressure flow equation, the correctness of the ACV system is verified by the simulation experiment of the air cushion pressure.Thirdly,based on the above models,a neural network PID controller is designed to control the air cushion pressure of the ACV, in order to reduce the vertical acceleration and stabilize the whole system.Finally, the PID-controlled air cushion pressure is compared to the one without PID control. The correctness and practicability of the proposed controller is then verified through the comparison results.