Delft University of Technology
Faculty Mechanical, Maritime and Materials Engineering
Transport Technology

C. Vreeken Development of anti-sway system on model crane
Masters thesis, Report 2004.TL.6915, Transport Engineering and Logistics.

The efficiency of cargo handling at ports largely depends on fast operation of the container cranes, together with small deviations in cycle time. One of the main problems in moving the load as fast as possible to the desired place is the sway of the container. To avoid this sway, several systems were developed in the past. In the laboratory of Transportation Engineering a model crane is available for research on different fields of the crane operation cycle.

This thesis has examined the use of input shapers as a way to develop an anti-sway system on the model crane. The importance of reducing the container's sway by controlling the trolley movement has been demonstrated. The simplest way to control a crane is by time-optimising, taking it as a rigid or flexible body. Starting from a non-linear model, this leads - linearized and simplified - to a second order differential equation with variables of the trolley displacement and sway angle.

Because a real-time system cannot be driven by discontinue impulses, the principal of input shaping can be used to control the trolley drive motion. Considering the effectiveness of different input shapers on aspects of duration, robustness and adaptability to the model crane in the labaratory of Transportation Engineering, two input shapers are chosen.

A time-optimal control method (TORB) is compared to the Zero Vibration and the Zero Vibration and Derivative shaper, which both use a second delayed acceleration step to cancel the caused oscillation. Performance indicators were defined to quantify the quality of the different control methods during five different cases of typical handling moves, varying the mass of payload and the accelerations of hoisting.
After regarding the consistency of the theory and the condition of the crane, there is no serious reason to see the imperfectness of the crane as a restriction to apply input shaping.

TORB is faster considering only the trolley movement trajectory, but after that it takes a long time until the sway has damped out, which can hardly be used in practice. ZV and ZVD shapers effect in better results, even when driving and hoisting are combined, and met the criterion of reducing sway under 5 mm in less than 3 s after motion. These anti-sway programs keeps some resonance as well, caused by the skew in the cables. ZV and ZVD shapers are more suitable for accurate positioning and meet the defined requirements for overshoot and settling time for the residual sway.

Reports on Transport Engineering and Logistics (in Dutch)
Modified: 2005.08.02; , TU Delft / 3mE / TT / LT.