Application of Image Pattern Correlation for non-intrusive deformation measurements of fast rotating objects on aircrafts

Abstract

The deformation of aircraft structures occurring during the take-off, flight and landing phases is of high interest for safety and efficiency considerations both for examination of existing as well as for design of new aircraft. To measure the deformation of large parts like e.g. wings, strain gauges and accelerometers are commonly applied. The installation of these sensors and their wiring is a very time consuming process which often yields to undesired modifications of the aircraft structure. Moreover, this technique is not applicable for planar measurements of fast moving objects, such as rotating propellers. DLR recently introduced an advanced optical non-intrusive measuring method called Image Pattern Correlation Technique (IPCT), which is based on photogrammetry in combination with cross correlation algorithms. IPCT has been combined with the Quantitative Video Technique (QVT) which means very accurate triggered recording e.g. performed with the DLR patented Video-stroboscope. The feasibility of this method for the investigation of propeller and wing deformation has been checked during ground and in-flight tests on real aircraft such as Piaggio P-180, Airbus A320 and Airbus A380. These experiments have partly been performed within the EU funded Specific Targeted Research Project AIM (Advanced In-flight Measurement Techniques). The specially designed and built video-stroboscopic multi-camera image acquisition system as well as the evaluated results will be described in detail in the full paper.