Multi-Frequency Phase Unwrapping Study In Grating Projection Measuring Systen For Aero Engine Blades

With the development of the civil aviation industry, aviation engine repair technology forthe development of the civil aviation industry is becoming increasingly prominent. However, asone of the key technologies of aero-engine repair, aeroengine blades welding repair technologyin the development of our country is not yet matured and technical blockade by othertechnologically advanced countries. To change this situation, developing domestic aeroengineblades welded repair technology is of great significance to improve the competitiveness of ourcivil aviation. The measurement work before welding is particularly important, to achieve theblade welding repair.In this paper, high precision and fast three-dimensional measurement in aeroengine bladesas background. Adopt the grating projection measuring technology which is widely used in theindustry. Analysis and study in phase unwrapping technique which is one of the key technologiesin the grating projection measurement technology. Selection phase unwrapping make thatenables this measurement method satisfies the requirements of blade measured.In grating projection measuring system the quality of phase unwrapping direct impact onthe accuracy of measurement. In order to overcome the traditional phase unwrapping methodusing long time and Algorithms complex and computationally intensive, using a measurementtechnology which using a multi-frequency grating projection. Project different frequenciesgrating fringes to the surface of the measured object, determine the grating fringes orders byMoiré fringe information to get the unwrapped phase value. The forms of grating fringes havedual frequency, three frequencies and four frequencies in Multi-frequency grating projectionmeasuring technology. Simulation results is that the three frequency grating projectionmeasuring not only high precision and a small amount of calculation, suitable for the practicalmeasurement.Error analysis by simulation experiment, improved phase unwrapping algorithm. Reducedthe error in the original algorithm by a rounded corrected method, and verified the feasibility ofthe improved algorithm by simulation and the practical blade measurement experiments.