Civil Engineering Reference
In-Depth Information
6.3.5 Hydraulic drill booms
Bupec 36 and Bupec 50 from Montabert GmbH are suitable for fully automated drill-
ing. The drill feed position in this case is determined with angle sensors at the drill
boom. These transmit the digitised angles to the central computer, which calculates
the position of the drill boom. In order to permit free rotation of the feed by 360°
(rollover), the electrical signals are connected through 20-circuit electrical hinged
connections, which avoids the need for additional cables at the drill boom hinges
(since the drill boom can be rotated, inclinometers would not be suitable). In order
to fully determine the position, the position of the base machine would have to be
determined from a stationary device. This is dealt with simply by manually entering
the tunnel axis: the feed is aligned manually parallel to a laser beam, and a command
to the computer saves the drill feed position as tunnel axis and automated drilling can
begin. This process is called learning. The principle is independent of the location of
the drill jumbo. There are three operating modes with this system:
- Fully automated cycle: height and location of all holes are selected according to
programming or a stored drilling pattern and drilled. Prismatic and fan-shaped cut
patterns are also possible. Altogether 90 different drilling patterns can be stored and
called up.
- Semi-automatic: the height and location of the holes are manually adjusted, in which case
the drill feed can still be kept parallel by the control system (electronic parallel holding).
- Manual: All four types of movement are controlled independently of each other.
The advantage of microprocessor control is not the increased advance rate but particularly
the precision in holding the configured drilling pattern.
6.4
Control of roadheaders
The control of roadheaders demands elaborate measurement and control technology due
to the number of degrees of freedom and the method of working. The working conditions
are very difficult and the face is often hidden by dust development. The danger to the
driver sometimes demands remote control of the machine, which is not practical without
at least some automation. On the other hand, the precision of excavation is subject to strin-
gent requirements, which are now practical to comply with. Geometrical deviations from
the design profile or the design axis increase support costs and also have an effect on the
load-bearing behaviour of the support.
6.4.1 Movement parameters determined by the control system
A roadheader consists of a tracked vehicle with loading conveyor and control station
and a cutting boom with the cutting head. In order to completely capture the move-
ments of the cutting head, which is not possible optically due to the dust development
and other conditions, the movements of the cutting boom and of the machine have to
be captured.
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