R. van der Wekken
Automatische positionering van hijswerktuigen voor zware lasten.
Report 95.3.TT.4552, Transport Engineering and Logistics.
The main subject of this report is the automatic positioning control of
hoisting equipment for heavy loads. De control of a logistic proces is
mainly decentrally organized, with a hierarchical structure of the different
levels. The lowest level in this chain is occupied by the Automatic
Positioning System (APS). This system receives a transportation job from the
higher level: transport load A from position 1 to position 2. The subsystems
of a standard APS are the Sensor system, the Drive system and the Control
system (on a hierarchically higher level). The Sensor system gathers all
information (except the information presented by the higher level) that the
Control system needs to regulate the Drive system. This report deals mainly
with the interaction between the Control- and Sensor system, because a lot
of the problems are caused by them. In the driving branch there is a
progressive transition to the use of AC-drive, that has al lot of advantages.
This report contains a survey of hoisting equipment for heavy loads which are
controlled by cartesian coordinates (x-, y- and z-axis). These are the Stacker
Crane (Material Handling in warehouses), the Overhead Travelling Crane (storage
at fabrication facilities) en Handling Equipment in the container handling
(RMG, RTG en Ship-to-Shore Crane). Within the limits of automatic positioning,
hoisting equipment has a lot of influence parameters. One of these
characteristics is the sway of the load resulting in several parameters.
To be able to fully automate hoisting equipment, reduction of sway is very
important, resulting in a fast development of Anti-sway systems.
The most important features when chosing an APS are: performance, environmental
influences, static- and dynamic forces, costs and performance requirements of
the operator (desired accuracy and reliability).
The Stacker Crane as well as the Overhead Travelling Crane can be automated
very well. Especially the absence of the environment influence on the
sensors resulted that there are practically no problems on this field
anymore. Another advantage is the fact that the work done by these cranes
consists mainly out of steady movements.
The opposite holds for hoisting equipment in the containerhandling. There
are two main influence parameters that obstruct the use of APS:
New developments to handle these problems are the use of absolute positioning
techniques like transponders based on radiosignals. Besides that the use of
electronics and control systems is growing rapidly.
- weather influence during outside operations (wind, rain and snow);
- relative large forces and accelerations which are characteristic for
In general during fine-positioning the use of direct-positioning techniques
is increasing more and more, within this technique the distance between the
hoisting element and the load is measured directly without the intervention
of the hoisting equipment.
The second part of this report deals with the ACTIV transhipment concept
(container handling). The ACTIV-equipment can be automated very well based on
Reports on Transport Engineering and Logistics (in Dutch)
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