The PPS guidance system automatically determines the exact position and driving direction of a TBM in three-dimensional space, giving the operator all of the information required to keep his machine on course.
Two prisms are installed in the forward section of the TBM to measure location and driving direction, and a two-axis inclinometer measures roll and pitch. The prisms are continuously monitored by a wall-mounted motorized theodolite, which automatically references the system computer against predetermined coordinates. The theodolite, which may be positioned 25-300 m behind the TBM, periodically measures the stability of its own mounting by referencing a remote prism, and notifies the operator of any movement. Horizontal and vertical deviation, and TBM orientation, is presented to the operator graphically. A projected path display can be provided to guide a deviated TBM back to the design centreline.
Additional options are available to facilitate special customer configurations. These include remote office computer connection; transmission between PPS system and TBM computers; ring calculation software; direct input for jacking cylinders; and radio link from theodolite to PC.
The PPS guidance system with automatic profile management shows the three-dimensional coordinates of the roadheader cutterhead and its distance to the design tunnel profile along a given axis.
Data is provided by three major components mounted on the roadheader: a motorized total station; a two-axis inclinometer; and boom movement sensors. The display screen shows the movement of the cutterhead within the design profile at the given chainage, with its colour changing according to the distance to the profile. A range of messages keeps the operator informed about progress and position. The RH3 software has been developed and improved from previous versions of PPS guidance system programs.
Special precautions have been taken to ensure proper system operation in harsh tunnelling environments. A disturbance-immune data transfer system has been developed and integrated into the guidance system; radio links can replace cables; and all electronic components are electrically isolated from each other and from the main tunnel electrics. The system computer is housed in a sealed industrial enclosure with a 12 inch TFT display.
PPS GmbH is located at Flemingstrasse 135, 81925 Muenchen, Germany, tel +49 89 540 72 733, fax +49 89 502 9225, and has its HQ at Henschelring 15a, 85551 Kirchheim b. München, Germany
tel +49 89 127 66 14 40, fax +49 89 127 66 14 420.