Publications in Scientific Journals:

A. Eichhorn, J. Fabiankowitsch, D. Nindl:
"Deformation Analysis of Tripods under Static and Dynamic Loads";
FIG Working Week Eilat, Surveyors Key Role in Accelerated Developement (invited), FIG Working Week (2009), 1.

English abstract:
The deformation of tripods may significantly affect high precision measurements. Therefore it is necessary to have profound knowledge about the effect of static and dynamic loads
(magnitude and temporal progress). This may be e.g. vertical deformations or torsions
induced by mounting a tacheometer and executing automatic measurement processes. The
effects are dependent on the stability of these `accessories´, which often are provided in a
wide bandwith by the manufacturer, starting from a lowcost tripod up to a highend tripod for
industrial measurements.
This study investigates the effect of static and dynamic loads on different types of tripods and shortly outlines the reasonable application in relation to different measurement tasks and
accuracy requirements. The work is a cooperation between TU Vienna and Leica Geosystems AG. For a priori theoretical simulations a Finite Element model of a tripod is created to design the experimental investigations. Because of the complexity of the mechanical system, the model is firstly restricted to the simulation of vertical static loadings.
For the investigations of height stability, different sensors are evaluated. Considering
measuring accuracy and capability for automatisation, it is decided to use a Leica DNA03
(digital level) to measure the vertical deformations. The determination of torsional effects and horizontal drift is performed by an electronic collimator from Leica with a sampling rate of 16 Hz. This sampling rate also enables the detection of dynamic effects as a result of tacheometer movements. The measurements are applied to autocollimation mirrors, mounted on the tripods. It is shown that the tripod deformations are not negligible if high precision results are required.

tripods analysis

Created from the Publication Database of the Vienna University of Technology.