New measurement and control technology in tunnelling - Tunnel Engineering: Basics and Additional Services for Design and Construction - page 265

Machine position . In order to unambiguously determine the position and orientation of
the roadheader, at least two previously defined points on the machine are surveyed. A mo-
torised theodolite is installed in the tunnel, which automatically sights two prisms installed
on the machine (Fig. 6-23). The location of the theodolite and its orientation are part of
the normal tunnel traverse. In order to check and determine relative position changes of
the theodolite due to deformation of the tunnel, known backsights further back in the tun-
nel are continuously sighted. Since the relationship of the prisms to the internal machine
system is known, it is thus possible to continuously transmit the current position of the
machine to a computer system.
The pitch and roll of the roadheader are determined by a precise electronic two-axis incli-
nometer. This is permanently installed on the machine and calibrated (Fig. 6-23).
As a result of the continuous measurements, the position, direction, pitch and roll of the
machine can be determined exactly and made available continuously for calculation.
Figure 6-23 Example of the placing of roadheader control components [68].
Cutting boom position. In order to determine the position of the cutting boom, robust
but sensitive sensors are installed. Angle gauges for horizontal and vertical slewing move-
ments and a sensor for the telescopic travel of the extending boom send changes to the
computer system.
Implementation. An industrial computer installed on the machine integrates the machine
position and cutting boom data and calculates the three-dimensional coordinates of the
cutting head. The data is then compared to the configured design alignment and the associ-