Research On Digital Measurement Of The Assembly Deformation Detection In Large Spacecraft Cabin

The spacecraft cabin is one of the most common structures in aerospace.It conforms to the development direction of high precision and digitalization of the aerospace industry by researching digital measurement of the assembly deformation detection in the spacecraft cabin,which can be used for assembly quality assessment and design scheme adjustment.Therefore,digital photogrammetry method is used to obtain the cabin surface information.This thesis conduct in-depth research on several crucial issues such as layout of measurement target points,registration of measurement data and assembly deformation detection,etc.The main research contents of this thesis are as follows:(1)In order to arrange the target points more reasonably in the application of photogrammetry,the finite element analysis is used to simulate the assembly deformation,and the simulation results are combined with the point cloud reduction method to propose an adaptive sparse measurement target point distribution method to make the target points more reasonable,which can achieve good measurement results with fewer measurement points;(2)In order to register measurement data under the condition of local deformation and displacement in the assembly process,a new matching algorithm for sparse measurement point data has been proposed,which can keep the point pairs that do not change the relative position before and after assembly,and then use these point pairs to calculate the transformation matrix to align the measurement data;(3)In order to evaluate assembly deformation,deformation error analysis at different assembly stages is calculated with the full use of the corresponding point pair information,combined with the surface reconstruction method,and the shape errors are calculated based on the photogrammetry data;(4)By assisting in the placement of measurement target points,registering measurement data and evaluate the assembly error with a software system,which developed with the methods in this thesis,the feasibility of proposed methods is verified in the spacecraft cabin assembly site.