Abstract: A process for anti-sway control of a rotating boom or other three-degree-of-freedom crane wherein the load is hoisted, at variable hoist lengths, by a cable suspended from a point that can be moved in space in three dimensions, either freely, or under known constraints. Initial acceleration of the load induces an initial sway to the load. A second lateral acceleration, equal to the first lateral acceleration, is scheduled to be applied one-half a sway period later to remove the sway induced by the first acceleration. A third acceleration is applied to correct for half the excess sway induced by hoisting, by non-linearities in the pendulum, and by crane platform motion; and a forth acceleration, of equal magnitude as the third but in the opposite direction, is scheduled for one-half a sway period later, to correct the remaining half of the excess sway energy. The first and third accelerations are constrained by the ability of the crane to execute them and to execute the delayed second and fourth accelerations.

Abstract: A process employing a computer controlled crane system for controlling the motion of a movable trolley from which a load is suspended at a variable hoist length therefrom to meet a selected arbitrary horizontal velocity reference while preventing sway of the load involves the steps of first, determining a lateral acceleration to reduce by a factor of one-half the sway energy contributed by (1) hoisting a load while the load is swaying; (2) non-linearities in the pendulum motion; (3) external forces such as wind, crane motion; and (4) non-vertical lifting of the load. Second, an additional acceleration of the same magnitude, but of opposite sign, is applied one-half a pendulum period latter to correct the remaining of the excess sway energy.

Abstract: A system is disclosed for accurately measuring the position of a moored container ship relative to a fixed pier after loading or unloading each container on the ship and including a processor mechanism employed to combine the measured relative position with previously acquired data indicating the ship position prior to the loading or unloading of the previous container, and utilizing the combined data to facilitate automatic control of placing or removing a subsequent container on the ship by a crane structure. The system is applicable for measuring six degrees of freedom of movement of any large object.