When crane payloads are lifted off the ground, the payload may unexpectedly swing sideways. This occurs when the hoist cables are at an angle relative to vertical and the payload is not directly beneath the hoist.  Because the hoist point is far above the payload, it is difficult for crane operators to know if the hoist cable is perfectly vertical before they start to lift the payload.  Some amount of horizontal motion of the payload will always occur at lift off.

If an off-centered lift results in significant horizontal motion, then it creates a hazard for the human operators, the payload, and the surrounding environment. This paper presents dynamic models of off-centered lifts and experimental verification of the theoretical predictions. The inverse problem of lowering a payload down to the ground can also be very challenging, for example when laying down a long, distributed payload from a near-vertical orientation in the air, to a horizontal position on a flat surface.

This paper presents motion-control solutions that aid operators to perform challenging lay-down tasks.

William Singhose
Professor
Georgia Institute of Technology
Woodruff School of Mechanical Engineering

Kelvin Peng
Graduate Research Assistant
Georgia Institute of Technology
Woodruff School of Mechanical Engineering

Anthony Garcia
Graduate Research Assistant
Georgia Institute of Technology
Woodruff School of Mechanical Engineering

Aldo Ferri
Associate Professor
Georgia Institute of Technology
Woodruff School of Mechanical Engineering