Dynamics Model and Control of High-Speed Supercavitating Vehicles Incorporated with Time-Delay

High-Speed Supercavitating Vehicles (HSSVs) are characterized by substantially reduced hydrodynamic drag from the fully wetted underwater vehicles. Drag is localized at the nose, where a cavitator generates a cavity that completely envelops the body. In this paper, a vertical plane model incorporated with time- delay effect (memory effect of cavity- vehicle interaction) is developed. Unlike previous models, the authors focus on the immersion angle between supercavity and vehicle used to determine the planing force. Stability analyses are carried out with the delay-dependent pitch-plane model. And a key problem is shown that this time- delay leads to destabilization of limit- cycle motion. A new PID control-algorithm with up-and-down rudder mode is designed, demonstrated by both numerical and experimental studies. The research may be useful for developing the trajectory control system of HSSVs.