Dynamics and control of crane payloads that bounce and pitch during hoisting

The natural sway of crane payloads is detrimental to safe and efficient operation. Most crane control research has focused on oscillation induced by motion of the overhead trolley that is perpendicular to the vertical suspension cables. Litde consideration has been given to bouncing oscillation in the hoist direction and pitching oscillation with respect to mass center of the payload. These dynamic effects arise in cases when the suspension cables are very long. These oscillations may interfere with the ability of the crane operators to accurately unload the payload at its desired position and orientation. This paper presents a method for generating shaped commands that suppress payload oscillations of bouncing and pitching. Theoretical models are initially used to develop and evaluate the input-shaping control algorithm. Then, experiments performed on a portable tower crane are used to demonstrate the improved response provided by the proposed approach.