Research On Aircraft Components Digital Preassembly Based On Measured Data

During the process of aircraft components assembly, the interference caused by manufacture deviation, the installation error of fixtures, and the position error of parts are frequently generated. In this occasion, certain parts are in need of fettling or position adjustment so that the assembly can be conducted smoothly. Nonetheless, repeated trial assembly and fettling tremendously affect the efficiency and costs. Aiming at solving this problem, this dissertation proposes a digital preassembly method based on measured data. The scanning point cloud models were assembled using virtual technology, and the interference distribution of them were calculated. Based on the interference, the handling of follow-up assembly could be guided quantitatively. The main contents are as follows:Some digital measurement systems widely used in aircraft manufacture and assembly are stated and the preprocessing of measured data is analyzed. To the point cloud data measured by FARO Edge2.7 in this paper, the appropriate preprocessing method is given.An interference detection method based on measured data is proposed. Take the composite wing box as an example. Firstly, the manufacture deviation is analyzed quantitatively. Then, an interference detection method is put forward. In this approach, the posture of a point cloud model is identified by assembly features. Accordingly, the value and distribution of interference are calculated. Based on this,calculation programmes are developed using MATLAB.The handling method of interference are researched. To the problem caused by passive compensation of assembling fit-up gaps, this chapter proposes a beforehand method. The panel's posture is adjusted to an optimal position, and the pose information is output through the locator. Then sacrificial layer is placed on the surface of skeleton, and the process redundancy is removed quantitatively by calculating the interference between the panel and the skeleton.The digital preassembly process of wing box based on measured data is researched. The main contents are as follows: the measurement and preprocessing of point cloud, the deviation and deformation detection of parts, the interference calculation between the panel and the skeleton, the position adjustment and the compensation of assembling fit-up gaps.