Analyse des dispersions quasi-statiques des machines-outils multi-axes (French text)

The main objective of this thesis is the development of a model for the diagnostic and monitoring of the geometric status of a machine tool, by using data acquired by touch probing. The touch probing can be performed on built-in fixed parts of the machine tool structure located in its work envelope, or on special artifacts. An initial testing session constitutes the reference data set, with respect to which the model analyzes the results coming from subsequent test sessions.; Using as input the probing results and the already known machining center nominal data, as for example its topology, geometry and joint coordinates, the model evaluates and predicts the geometrical performance of the machine by developing three diagnostic levels. The first level is concerned with the resulting errors at the touch points, and indicates the moving axes status. Following several test sessions, this level presents graphically the historic status of each axis geometric performance and points out the degenerating axes. The second level points out which are the faulty geometric parameters, or parameter sets, which are the cause of the geometric status degeneration of the machine tool. Finally, the third level estimates the effect of the machine tool geometric degradation at points situated on the part features to be machined or measured by the machine.; The present research is developed considering the latest knowledge in the field of machining dispersions. The original contribution concerns all three levels of the model. For the first level, the originality of the diagnostic and follow-up procedure consists in the development of a touch probing strategy and in the use, for measuring purposes, of features having certain orientations with respect to the moving axes. The second level is original in all that covers the geometric parameter evaluation and the development of the moving axes sensitivity matrix. The propagation of the geometric parameters in order to estimate the variations on the work piece, at the third level of the model, is original for the part concerning the positioning tolerances and the evaluation of the effect of the machine tool geometric status degeneration on the part features.; The presented methodology is validated both by a numerical simulation and by practical experiments.