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
2.6.4 Guidance of a non-omnidirectional Vehicle
A non-omnidirectional vehicle has the fundamental disadvantage that it is unable to drive
sideways to the segment. This is why the vehicle has to be steered towards the segment's
direction at first to minimize deviations. Consequently additional time is required. As shown
below it is even possible that the vehicle increases the deviation at its rear axle at first.
Figure 24
Forward guidance of a non-omnidirectional vehicle
At first the driving direction to which the steered wheels before the fixed axle are directed
at (usually forward travel). Since a fixed axle cannot be steered sideways here the vehicle
control only depends on the point "Virtual Point Front". The position of the rear axle follows
the front in that it is dragged virtually. The vehicle control itself corresponds to the guidance
of an omnidirectional vehicle. In this direction the vehicle control remains stable, as the fixed
axle automatically follows the point "Virtual Point Front". When driving backwards the guid-
ance would not be stable, as the non-steering axle would move to one side or the other.
Thus the vehicle control to the opposite direction looks is as follows:
Figure 25
Backwards guidance of a non-omnidirectional vehicle
When the vehicle travels backwards, it is mirrored at the fixed axle. Figure 25 above shows
the real vehicle plotted with thick lines and the mirror-image with thin lines. In this case the
vehicle control is depending on the point "Virtual Point Rear". If this point is controlled the
fixed axle follows and the control is stable again. The mirrored wheels always steer with op-
posite signs but with the same steering angles.
2.6.5 Driving Modes
The normal operation of the vehicle consists of two different operation modes. The idle
mode (see section 2.6.5.1) and the automatic mode (see section 2.6.5.3). The modus Param-
eter Test (see section 2.6.5.2) is only called up during commissioning. Remote Control, this
is the modus for the remote control (see section 2.6.5.4). Vector steering, in this mode the
vehicle drives to the target on a straight line (see section 2.6.5.5).
Forward Dis. Fix
Forward Dis. Var
Virtual Point Front
Direction
Target Position
Actual Position
Virtual Point Rear
Segment
Deviation Front
Direction Front
Vehicle X
Vehicle Y
Forward Dis. Fix
Forward Dis. Var
Virtual Point Front
Direction
Target Position
Actual Position
Virtual Point Rear
Segment
Deviation Front
Deviation Rear
Direction Rear
Vehicle X
Vehicle Y
