Measurement of rotor blade deformations of wind energy converters with laser scanners

Abstract

Wind energy converters in operation are exposed to high stresses which result in large deformations of the rotor blades. In this paper, a method for determination of deformations of rotor blades is presented using multiple synchronous laser scanners and cameras. A special focus is brought into the twist of the blade and the according deflection. In a first step, multiple scanners in 1D mode are used which record cross sections at different positions along the rotor blades. By comparison with the CAD model, deformations can be derived. In order to ensure that the positions of the cross sections are defined in the coordinate system of the wind energy converter, the nacelle is pre-scanned and a transformation is performed using known coordinates from the manufacturer. To account for the relatively slow movement of the nacelle, it is observed by a photogrammetric camera. The results of the nacellés motion are considered in the analysis of the 1D data. First test recordings were carried out with different measurement frequencies to enable comparisons of accuracy. Furthermore, the first results of the cross-sections are presented.