Research On Key Technologies Of Aero-engine Blade Profile Based On Laser Scanning Measurement

The development of aero-engine is one of the most important strategic deployments in aerospace countries,and the level of its blade manufacturing plays a crucial role.At present,the blade of aero-engine manufacturing cannot usually be done in one step,and it needs to be measured after pre-processing.The measurement results can be used as a further guide for the following processing.With the wear of the blade,it should be repaired to getting a better performance.But every blade should be repaired have different repair allowance,and it should be also extracted by a measurement processing to guarantee the repair accuracy.Therefore,the engine blade measurements play a crucial role in the blade manufacturing and maintenance process.In this paper,the measurement of aero-engine blade is regarded as the major investigators.The tilt error of laser sensor is calibrated for error compensation.The morphology characterization and the point sampling strategy of blade measurement are taken into account.Also,we made a further research in the alignment of measurement cloud data and the extraction of model error to make sure that the measurement of the blade will be more precise.Finally,we develop a software to make the measurement more convenient,which is based on Qt 5.2.0 development environment.The main content and innovation of this paper are summarized as follows.1)The error of tilt which is caused by the condition when the angle of incident light of laser displacement sensor and the normal of measured surface is not equal to zero.We make a research on the influence of the lens' internal and the tilt angle which may cause received spot shifting,and we also quantified the tilt error value which can be used for measurement compensation of free-form surfaces such as aero-engine blades.Finally,a laser interferometer's contrast experiment was used to verify the validity of the error model.2)The method of characterization of aero-engine blade profile and the distribution of data points in the profile measurement are studied in this paper,which can effectively reduce the data volume of point clouds to achieve a higher computational efficiency.3)The position and pose matching between the point cloud data collected by the displacement sensor and reference model is studied.The initial and fine registration based on the ICP algorithm are applied to ensure the consistency of coordinate system between the measurement point cloud and the reference model point cloud.4)The NURBS curve was used to characterize the profile of the blade,and we make a research on the calculate process.With the theory and algorithm which mentioned before,we develop a blade measurement software,and the self-adaptive trajectory code of the blade measurement can be programmed with this software.Finally,the measurement error was extracted by Geomagic Qualify software to verify the validity of the measurement results.