Control System Design for WIG Aircraft on the Wavy Water Surface

Wing-in-ground (WIG) aircraft is an air vehicle flying near the surface to obtain the ground effect. Its purpose is to gain an improved aerodynamic lift-drag ratio. During flying over wavy water surfaces, this kind of aircraft is affected by random waves resulting in complicated dynamic characteristics and poor longitudinal stability. Therefore, it is essential to investigate its stability and manoeuvrability for the safety of WIG aircraft. This paper focuses on this crucial but challenging issue. As a stepping stone, a 6-DOF mathematical model to describe the WIG aircraft considering the wave disturbance is established. Based on the linear model constructed in state-space form, the stable controllers are developed, including a pitch hold controller, an altitude hold controller, a roll angle hold controller, and a heading controller. Moreover, the closed-loop control system is stable despite wave disturbance. Finally, simulation results are shown to verify the effectiveness of the designed controllers.