Research On The Key Technology Of Automatic Laser Scanning Measurement For Aircraft Skin Shape

Digital measurement technology is widely used in aeronautical manufacturing,which provides high efficiency and high precision measurement for aircraft parts detection and is gradually replacing the traditional detection method based on the analog quantity transfer.As for the digital measurement of aircraft skin,there are still the following problems: the development and application of most digital measuring equipment is not enough and the automatic application of measuring equipment is less,which leads to the failure to form a unified measurement process and test specification;the measurement data of some key features lack reasonable and effective data processing methods.To solve the above problem,a digital measurement method is proposed based on laser tracker and laser scanner(T-Scan),the laser scanner is clamped on the robot to measure the parts according to the planning path.The main research object of aircraft skin appearance is surface feature and contour feature.A measurement scheme is designed.First,the detection feature's CAD model is discrete to data point.Second,a scanning path is formed based on discrete points.Third,digital scanning is carried out by T-Scan and the quality of product is evaluated by the analysis of the measured data.The main contents of this paper are as follows:(1)A research into automatic measurement of aircraft skin shape based on laser scanning.The requirements of the skin shape measurement are analyzed,and then an automatic measurement system is built,a complete skin appearance measurement process is formulated.(2)A research into method of digital definition of skin shape features for measurement.Recognition and extraction of skin shape features is applied.For the features of curve and surface,an adaptive digital discrete method is proposed.(3)A research into method of scanning path planning adapted to T-Scan.Combined with the information of digital discrete points and measurement constraints of laser scanner,a scanning attitude planning method based on region growing method and a scanning path planning method based on region division are put forward.(4)A research into processing method of T-Scan measuring point cloud.The structure characteristics of measurement point cloud data are analyzed,and different data processing methods are proposed for the surface feature and contour feature.The software of measurement and analysis is developed to realize the visual processing.