Research on control of longitudinal motion of underwater high-speed vehicle

In flying, the underwater high-speed vehicle inside a cavity, leads to the overall drag can be an order of magnitude less than the drag for a fully wetted vehicle, enabling the vehicle to achieve a surprisingly high speed under water. But it changes the balance of hydrodynamic forces, so it is really hard to model and control the underwater high-speed vehicle. In this paper, the dynamic model of the vehicle longitudinal motion are presented by using cavitator and vector thrust controlling together. The distribution of widths of the clearances between the underwater high-speed vehicle surface and the cavity boundaries is calculated. The depth of the model immersion into the water through the cavity surface is small, so the planning force is considered to be system disturbances. The robust mixed-sensitivity approach is used to design the controller, and then simulation is done for the system. The simulation result shows that the robust controller could overcomes system disturbances, improve the dynamic stability and control quality of underwater high-speed vehicle.