Controller design for anti-heeling system in container ships

Excess heeling in container ships often occurs in the process of unbalanced marine cargo loading and unloading, which is a great restriction to rapid loading work and is even detrimental to the security of the ship. In order to increase the loading and unloading speed, as well as ensure the container ship's safety during the process of container stevedoring, this paper investigates two different controller design scenarios for the high efficiency anti-heeling system employed in the container ship. One is a valve switched anti-heeling system with a logic controller and the other is a reversible pump anti-heeling system with a PID controller. Simulation is conducted to illustrate each controller's performance in terms of following the input command and rejecting external heeling moment disturbance. Methods of tuning the related coefficients for controllers in the list control system are given in searching of a sound system's response to loading and unloading work. Simulation results can also be utilized to choose among different types of anti-heeling systems, as well as each individual device, such as valve and pump.