A Controller Enabling Precise Positioning and Sway Reduction in Cranes with On-Off Actuation

Precise manipulation of payloads is difficult with large cranes. Oscillation canbe induced into the lightly damped system by motion of the overhead support point, orfrom environmental disturbances. A combined feedback and input shaping controller ispresented here. The controller uses feedback to detect and compensate for positioningerror in the overhead support unit (e.g. the bridge or trolley), and input shaping is usedto negate motion-induced oscillation in the payload. The controller is implemented on a10-ton bridge crane at the Georgia Institute of Technology. The controller generatessimple on-off commands, suitable for typical cranes that employ on-off, relay-drivenmotors. The controller achieves good positioning accuracy, and significant payloadsway reduction.