Anti-Sway System for Ship-to-Shore Cranes

Abstract

All ship-to-shore cranes hoisting mechanisms are made of a load attached to the trolley by means of a hoisting rope. In the process of loading and unloading the ship, the trolley moves the load along the boom from ship to shore and vice versa. During movement, the hoisting mechanism structure causes swinging of the load around vertical position. Load swing increases the loading/unloading time and increases the probability of collisions with other objects, like a nearby container, an iron construction for disposal of material (e.g. bunker), etc. Swinging of the load cannot be avoided, but can be radically reduced by using appropriate anti-sway systems. The paper derives a non-linear and linearized dynamic model of the crane load based on parameters of Panamax ship-to-shore crane in the Port of Koper. The responses of three open-loop anti-sway systems are compared together on the aforementioned dynamic model. Simulation results show that all three systems reduce load swing significantly, but only the systems based on zero-vibration-derivative and zero-vibration-derivative-derivative methods completely satisfy the given requirements.