Anti-Sway Control for Container Cranes

QUAY (CONTAINER) CRANES

Sway Control. SmartCrane’s solution for quay cranes begins with the basic open loop anti-sway implemented in the trolley drive, PLC, or in a separate Control Processor. This technology is represented in U.S. Patent No. 5,526,946. This solves much of the sway control problem with no sensors and no end of move jerky cab motion. Smooth and carefully limited acceleration patterns are easy on operators and crane structures alike.

Integration. PLC function blocks or add-on instructions make implementation easy and cost-effective.

Semi-Automatic Moves. Add positioning and hoist control to the mix to allow simple or complex destination-seeking automation.

Automatic Moves to Lane. The simplest and most cost effective is a simple one-button move from ship to a shore lane. A long button press selects the measured trolley position as the lane center. Over the ship, a single button press while hoisting takes over the hoist to safe height, then full speed automatically to the lane, beginning the hoist down at the optimal trolley position. The operator takes over at any point in the move, usually when the trolley is close to the lane center and the spreader nearly in position. With load cell or twistlock cues, the software can distinguish between two lanes, for separate import and export use.

Automatic Moves to Ship. Still with a single button control, SmartCrane software can move efficiently to a ship stack, beginning trolley motion optimized to reach safe height before reaching the ship (often called “parabolic move”). The software recognizes when loading or unloading above deck containers and sequences one container position in or out as appropriate. The operator initiates the process by moving to the first stack, to establish height and position. After that the software cycles according to standard procedure. For cell work, a secondary switch indicates the type of cycling needed. Alternatively, a complete set of destination buttons can be handled individually. As with the ship to lane move, the spreader comes to a safe stop close to the target position, with the operator taking over the final positioning manually.

Precise Positioning. With SmartCrane’s SmartCamera and a passive vision target on the head block, Small residual sway can be eliminated and the spreader positioned accurately in the center of a destination lane. Sensor systems to detect truck position or ship stack position can allow even more accurate spreader positioning.