Study on the dynamic behaviors of an USV with a ROV

In this paper, we employ a dynamics modeling method for investigating a multi-body dynamics system consisting of an unmanned surface vehicle (USV), an umbilical cable (UC), and an autonomous underwater vehicle (ROV). The ROV, which is towed by a UC for the purposes of exploration or mine hunting, is modeled with a Six-Degree-of-Freedom (6-DOF) equation of motion that reflects its hydrodynamics characteristics. The 4th-order Runge-Kutta numerical method was used to analyze the motion of the USV with its hydrodynamic coefficients which were obtained through experiments and from the literature. In modeling of the flexible UC dynamics, the governing equations of the UC dynamics are established based on the catenary equation method. The shooting method is applied to solve a two-point boundary value problem of the catenary equation. To reflect the hydrodynamic characteristics of the UC, the hydrodynamic force due to added mass and the drag force are imposed. Several simple numerical simulations were conducted to validate appropriateness of the modeling.