A videogrammetric system for measuring the full-field blade deformation of a heavy-duty helicopter's rotating rotor.

Abstract

In this paper, a videogrammetric system, based on three-dimensional digital image processing and industrial close range photogrammetry technology, is proposed to solve the three-dimensional motion and deformation parameters of a rotating blade by identifying a speckle pattern. For the high aspect ratio and flexible rotor blade design often used in heavy-duty helicopters, there are extremely complex aerodynamic, dynamic, and coupling problems that require solutions to measure the full-field deformation of the rotating blade in the test condition of a rotor test tower. The key issues involved include a two-step calibration method using separate internal and external parameters for a large field of view, and a reliable estimation of the seed point method for a large deformation and weak correlation speckle images match. The system was developed and a simulation test was conducted on a rotor test tower. The results show that the proposed system is practicable to measure the surface displacement and motion parameters of a high-speed rotating rotor blade.