Maneuvering and Control Simulations of a Hovercraft

Abstract Air cushion vehicles are unconventional vehicles that employ an air cushion under the hull allowing them to travel on different terrains making them highly maneuverable even at low speeds. The mathematical model developed in the study is capable of predicting the maneuverability of the air cushion vehicle. The dynamic model uses equations that account for surge, sway, and yaw motions of the craft. The influence of rudder, and duct propeller force, a erodynamic forces and dynamic coefficients on vehicle maneuverability have been considered. The results have been compared with in-field trials and provide valuable insight towards model calibration. INTRODUCTION Air cushion vehicles are unconventional vehicles that employ an air cushion under the hull, allowing them to travel on different terrains (Fein, Magnuson, and D. Moran 1974; Sira-Ramirez and Ibfiez 2000). This makes vehicles highly maneuverable even at low speeds, providing them with this unique advantage. While several mathematical models have been developed to study the motion of air cushion vehicles (Murao and Nojiri 1985; Waters, D. D. Moran, and Messalle 1983; Zilman and Miloh 1992), there are limitations in their ability to fully capture the complex interactions between the different forces experienced by the vehicle as it traverses on land. The mathematical model developed in this study uses Newton's second law and is capable of predicting the maneuverability of the air cushion vehicle. The hovercraft dynamic model explored in this research is both nonlinear and underactuated. The dynamic model represented uses equations that account for surge, sway, and yaw motions, including the influence of rudder, propeller force, and drag forces on vehicle maneuverability. Rudder forces play a significant role in hovercraft maneuvering, and their effectiveness is significantly influenced by the inflow velocity and the drift angle of the vehicle. The rudder forces evaluated account for not just the rudder parameters but also the inflow velocity to the rudders and characteristic lift and drag coefficients, rudder angle, and the position of the rudder with respect to mid-craft. Similarly, the mathematical model also accounts for the influence of aerodynamic forces and dynamic coefficients experienced by the craft and their effect on vehicle dynamics. The effect of fin-effect side force and yaw moment of the fan due to an inclined inflow to the fan has been modeled by the study.