Dynamics modeling and control design for a high-speed supercavitating vehicle

In order to explore dynamics modeling and control of supercavitating vehicles, memory effect of the cavity and its influence on the shape of cavity were researched based on the principle of cavity expansion independence. The cavitator orientation effect and cavity flotation were taken into account in computing the hydrodynamic forces of all parts of the supercavitating vehicle. Efficiency of the fin with the change of the fin immersion depth while the vehicle was traveling underwater was researched. A more precise nonlinear dynamics model of supercavitating vehicle was established. Robust pole placement controller was designed after exact input-output linearization. This controller has good control performance in depth tracking. Its shortcomings are input saturation and adverse effects of planing force. Model predictive control controller was designed to solve the problem of input saturation by restricting the distance between tail part of vehicle and the cavity wall, so that the planing force was avoided, the friction drag was reduced and the motion stability of the vehicle was improved.