guided vehicles (AGVs) are becoming increasingly common in the industrial
workplace. Small vehicles have been utilised inside factories as
an aid to transport components of completed assemblies for decades.
The environment on a factory floor can be set up to provide optimum
conditions for these machines to operate effectively. This may include
the placement of markers on the floor for the machine to follow
or retro-reflective strips for a laser scanner. Adverse weather
and uneven surfaces are rarely a problem in these situations.
AGVs are increasingly
being used in mines, ports and other unstructured environments.
For robust, reliable operation they must operate over the full range
of climatic conditions, including rain, fog and dust. To this end,
a sensor is required that can accurately measure surrounding features
under all operating conditions. The ability of an autonomous vehicle
to use such measurements in order to localise is probably one of
the most important aspects of AGV control.
sensor is ideal for outdoor vehicle guidance. In addition to the
navigation function, the radar can also be used for obstacle detection.
Safety of AGVs and those working around them is an important consideration.
If the sensor is placed at a suitable location on the vehicle it
can be used to perform both navigation and obstacle detection functions
The target beacons
used for navigation are designed to have high radar cross-section
and return a strong signal. If a signal is greater than the higher
of the thresholds and is up to 200m away then it is classified as
a navigation measurement. If a signal is greater than a lower threshold
and in the range up to 50m then it is of interest to the obstacle
detection system. Of course a signal less than 50m, but greater
than the higher threshold is of interest to both the navigation
and the obstacle detection processes and two messages are generated.
information and a comparison of the radar navigation system with
differential GPS position please follow the link.