Minimum-time trajectories for reducing load sway in quay-cranes

An investigation into near-minimum-time trajectory planning for a quay-crane is presented in this paper. A dynamic model that captures swinging and pitching motions of the load carried by the crane is developed. An algorithm to obtain near-minimum-time input commands for positioning the crane, that utilises the developed dynamic model, is presented. It is shown that only a modest reduction in the operating speed is required to move a crane without residual load sway. Furthermore, ignoring the reeving geometry and assuming that the quay-crane can be modelled as a crane carrying a point mass at the end of a single rope is shown to be inadequate. Computer simulations using the operating parameters of a full scale quay-crane are presented to verify the results.