Geometric control for highly accurate construction machine guidance


Exploration of control circuits for machine control under geodesic aspects.


General research of control circuits for machine control under geodesic aspects.
Design of the control loops for optimal integration of target-tracking tachymeters as position sensors.
Investigation of geometric management tasks in the accuracy range of a few millimeters.
For the three-dimensional guidance of modern construction machinery, such. As slipform pavers, Gräder, or Dozer be tracking tachymeter or GPS-RTK used. This applies, in addition to other sensors, such. As tilt sensors to integrate as position-determining sensors in the control loops for machine control.

For high-precision management tasks in the range of a few millimeters, only tachymeters can be used due to the measuring accuracy. But since even the most modern target-tracking tachymeters are not very suitable for a scheme per se because of their relatively low sampling rate of up to 10 Hz and a dead time of up to several hundred milliseconds, only very slowly moving machines can be geometrically guided with high accuracy.

The described dynamic behavior of target-tracking tachymeters causes the current position of the machine to be determined too late in curves - larger deviations from the desired trajectory must be compensated by the control.
 Figure 1: Closed-loop system with anticipatory precontrol
Closed-loop system with anticipatory precontrol

If the human control behaviour in case of manual machine control is analysed, unfavourable dynamic characteristics similar to a tracking tachymeter can be realized. A human is able to integrate the future track of the desired trajectory into his manual control behaviour – he anticipates. Hence a precontrol is established, that leaves only small deviations for recontrol. Figure 1 schematically shows a closed-loop system with anticipatory precontrol.

This theoretical knowledge is to be realized experimentally and later in practice and its potential is to be investigated.

Experiment with model truck:

Experimental realization is effected with the model truck (scale 1:14), show in picture 2. The truck is automatically guided on a predetermined trajectory. A tachymeter (Leica TCP 1201) is integrated into the closed-loop system. The deviations should not exceed 5 mm. The mentioned control concept with anticipatory precontrol is realized in LabView®. A detailed experiment description can be found in (Gläser 2003).

Modell-Lkw als Simulator (Quelle: iigs)

Erste Ergebnisse:

First results:

Figure 3 shows as a first result the deviation of the model truck to a reference trajectory. The deviations of automatic control with and without precontrol are compared. The speed was increased to 20cm/s, contrary to the speed of 1-2 cm/s used in practice (e.g. slip-form pavers). It can easily be recognized that the anticipatory precontrol increases the quality of automatic guidance considerable, and the aim of a maximum deviation of 5 mm can be reached despite a speed of 20 cm/s.

 Deviation of the truck to the given trajectory


  • Beetz, A., Schwieger, V.: (2008) Integration of Controllers and Filter Algorithms for Construction Machine Guidance. 1st International Conference on Machine Control and Guidance, Zürich, Schweiz, 24.-26-06.2008.
  • Schwieger, V., Beetz, A.: (2007) Optimierung von Regelalgorithmen zur Baumaschinensteuerung am Beispiel eines Simulators. Beiträge zum 15. Internationalen Ingenieurvermessungskurs, Graz, Herbert Wichmann Verlag, Heidelberg,
  • Gläser, A.(2005): A Modular System for Guidance and Control Applications for Construction Machines. In: Grün, Kahmen (Eds.): 7th Conference on Optical 3-D Measurement Techniques, Volume I, pp. 307-316, Vienna. (Kurzfassung)
  • Gläser, A., Schollmeyer, R. (2004): Messwerterfassung und –synchronisation in Multisensorsystemen. In: Beiträge zum 58. DVW-Seminar, Kinematische Messmethoden – Vermessung in Bewegung, Wißner Verlag, Augsburg.
  • Gläser, A. (2003): Steuerung autonomer Baumaschinen - Ein Simulator. In: Virtuelle Instrumente in der Praxis, National Instruments-VIP2003, Hüthig Verlag, München.

Diploma Thesis:

  • Beetz, A. (2003): Entwicklung ausgewählter Komponenten eines Regelkreises zur Fahrzeugsteuerung und deren Realisierung in einem Testsystem. Diplomarbeit am IAGB, unveröffentlicht.
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