Documentation HG G-73650ZD | English, Revision 05 | Date: 09.03.2017 | www.goetting-agv.com
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Chapter 2: Basic Principles of Track Guidance
ATTENTION!
When using a combination of Transponders and GPS the transponders have to be posi-
tioned inside the country coordinate system or the basic coordinate system in order to keep
errors as small as possible!
The errors in between the transponders then are insignificant. In contrast if the Transpon-
ders are positioned in a different coordinate system the resulting error across the area is
problematic.
2.5 Reconstruction of the Route (Segments)
Segments are the connecting paths between branches and end points. Tracks are built by
combining matching segments from start to finish. The segments are created with a special
CAD program. We will refer to
Malz++Kassner® CAD 6
for which Götting provides a plug-in
for the navigation controller. Each segment consists of several support points that define the
segment course and contain information such as orientation, speed and attributes. Each
segment consists of min. 4 and max. 1000 support points.
2.5.1 Virtual Tracks
A virtual track is a route that is not defined by actual tracks or marks (e.g. lines or guide
wires). It is usually constructed in a CAD program, where the desired track is drawn directly
on a ground plan. Later on the vehicle will follow this virtual track as if it were driving on a
real track or „rails“. Thus the CAD program has to incorporate the special features of each
vehicle to make the track guidance as accurate as possible.
Figure 11
Example: Virtual track with support points
The virtual track consists of several segments that define the sections between branches
and terminal points. Each of the segments must consist of at least four support points
which are positioned at equal distances over the whole track. These support points are not
actual points on the route (for example transponders in the ground). The distance between
them depends on the type of the route and the vehicle used.
The closer the support points lie to one another the more precisely the tracking will correlate
with the virtual track. However, very close distances between the points are unnecessary
where large vehicles are concerned because the vehicle cannot be driven that accurately.
However if the distances between the points are too big, the CAD program would display
them as angular curves because then no curved routes can be calculated from points which
are wide apart from each other.
Vehicle
Segment change
Support points
Segment 1
Segment 2
