Anti-Sway System for Container Cranes with Coordinated Motion Control and Reduced Dynamic Loads

A novel anti-sway control system for cranes is proposed. The proposed method is based on the formation of a predetermined sway angle as a piecewise-continuous function, the second derivative of which does not experience discontinuity. Its third derivative is a rectangular pulse of certain variable-sign amplitude, which results in eliminating the mechanical stress in the crane construction and kinematic gears. A comprehensive mathematical model and an experimental prototype of the crane are developed. Simulation and experimental results prove that the proposed anti-sway method enables damping of the oscillations of the suspended load during its horizontal motion (in two orthogonal coordinates) and hoisting/lowering. The control method is invariant to the mechanism/load mass ratio, lift height and hoisting speed.