Modelling of a captive unmanned aerial system teledetecting oil pollution on sea surface

Abstract

Recent major oil-spills were tracked using observations with sufficient altitudes over the sea surface, to detect oil slick locations. For oil-spill responders, we propose a captive Unmanned Aerial System, UAS acting like a periscope over a ship or supply vessel. The system is composed of an umbilical deployed from ship deck, and there are few studies that have examined elasticity within cable dynamic during take-off or landing (TOL) and normal flight phases. Therefore, the safest approach for the control-commands of the system is through umbilical dynamic modelling. We give a time-dependant finite-element formulation, using improved elastic non-linear cable elements. Two kinds of boundary condition, natural or essential, are discussed for roll-in or roll-out of the umbilical. A numerical convergence and a validation with an exact solution are provided, using two examples for the flight parameters. Finally, sensitivity of the model potentially extends its capacity for the system equilibrium prediction, under wind primary influence.