Crane motion control

Abstract

Methods of detection and prevention for snags or off center lifts, and auto-centering a crane over a load. Snag detection includes monitoring angular deflection of the load with respect to an at-rest position, and halting movement of the crane in a direction of increasing angular deflection. Controlling off center lifting includes detecting a side load condition for a load, and preventing a hoist operation when the side load condition is detected. Auto-centering a load includes determining a position of a block coupled to the load with respect to a trolley of the crane, and centering the trolley over the block prior to a moving operation. Centering includes comparing a position of a block marker using a trolley camera to a known centered position of the marker with respect to the camera, and moving the trolley to match the determined position of the marker to its known centered position.

Dependencies are inferred from the claim text.