Published on September 2011 | Marine Salvage, Lift Bags, Marine Hydrodynamics

Sliding Mode Controller for Salvaging of Sunken Vessels

This paper presents a mathematical model and numerical time-domain approach to simulate the dynamics of a sunken ship/vessel being raised from the seafloor by a gas inflating system. Based on the simplified four-degree-of-freedom equations of rigid-body vessel motion, a sliding mode-depth controller is designed to ensure the hydrodynamic stability within the assumed diving vertical plane. Numerical simulations are carried out by solving the standard State Dependent Ricatti Equation in a body-fixed coordinate reference frame. Preliminary results in terms of coordinate positions or trajectories, velocities and angular velocity components of the raising body are evaluated based on an experimental pontoon model. The efficacy of the sliding mode controller is investigated for the exemplified marine salvage operation