Observer-based Boundary Control of a Water-powered Aerial System

This paper investigates the motion control problems of an aerial system powered by water jet propulsion in which the water is conveyed through a flexible hose attached underneath. In this system, the thrust is generated by jetting water out of four nozzles, whose cross-sectional area is much smaller than the inlet, while the necessary torques for fight maneuvers are achieved by rotating these nozzles to direct the respective thrust. The system can be thought of as a tethered drone and its dynamics are described by coupled ordinary–partial differential equations showing the motion interaction of the hose and the system. Based on Lyapunov’s direct method, an observer-based boundary control is designed to achieve the desired flight maneuver of the system while still preserving the stabilization of both the system and the hose. As a result, the uniform ultimate boundedness of the entire control system is achieved, and its performance is verified by simulations.