A controller enabling precise positioning and sway reduction in bridge and gantry cranes

Precise manipulation of payloads is difficult with cranes. Oscillation can be induced into the lightly damped system by motion of the bridge or trolley, or from environmental disturbances. To address both sources of oscillation, a combined feedback and input shaping controller is developed. The controller is comprised of three distinct modules. A feedback module detects and compensates for positioning error; a second feedback module detects and rejects disturbances; input shaping is used in a third module to mitigate motioninduced oscillation. An accurate model of vector drive and AC induction motors, typical to large cranes, was used jointly with a deconvolution analysis technique to incorporate the nonlinear dynamics of crane actuators into the control design. The controller is implemented on a 10-ton bridge crane at the Georgia Institute of Technology. The controller achieves good positioning accuracy and significant sway reduction. r 2006 Elsevier Ltd. All rights reserved.