The demand for rapidly increasing data communication speed between spacecraft and ground stations leads to the
development of highly stable parabolic satellite antenna structures. Besides the requirement for a very accurate overall
shape precision, one of the main design challenges for these antennas is their shape stability under varying thermal
conditions (in-flight operation). Although accurate mathematical models (FEM), already established during the design
phase of the antennas, allow predictions of their behavior under varying operational conditions, even minute variations of
the introduced material property constants can lead to significantly varying simulation results. For the validation of the
mathematical model, a Pulse ESPI system has been used to measure the thermal distortion in a space simulation
chamber. ESPI measurements have been recorded during two consecutive cooling down cycles under vacuum condition
(less than 10-4 hpa remaining pressure), each cycle covering a temperature range from approx. +110°C to approx. -
110°C. The evaluated data sets allowed determination of the overall distortion of the antenna and its deformation in
temperature intervals of approximately 0.3°C at any time of each cycle. After evaluation of the interferometric data, a
comparison with the deformation predictions from the FEM simulation has been carried out.
An optimum of preparation of the body in white is indispensable for the manufacturing of a customer relevant quality of painted surfaces. For the reduction of the refinishing operations during and after the painting processes, and to guarantee a constant quality level, it is necessary to detect and eliminate surface defects already in the body works finish. Within the project 'Automatic Body Inspection System' (ABIS), a system is developed, which automatically detects, classifies and marks invisible surface defects on bodies in white, so that a propagation of these defects into the painting process can be prevented. For this reason, an optical measuring system for the visualization of sheet metal defects, a sophisticated software package for the recognition of surface defects, and the system technology required for the automation of all functionalities (like measurement, identification, classification and marking) is developed. The system is trainable, hence collects the knowledge of experienced quality testers and translates it into objective judgement criteria to allow for a constant quality level.
Optical measuring systems, such as holographic interferometry, speckle interferometry and speckle correlation make it possible to achieve the graphic, 3-dimensional surface area and very accurate measurement of deformations and vibration amplitudes. These systems are suitable tools for the optimizing of construction features.
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