Research On Gap Control Technology Of Lid Assembly Based On Digital Measurement

With the continuous improvement of aircraft flight performance,the manufacturing precision and assembly quality of skin parts have become the focus of manufacturing research.Aiming at the problems of insufficient trimming accuracy of flaps and difficulty in controlling the assembly gap between flaps and peripheral skins in the aviation manufacturing industry,this paper takes flap assembly gap control as the research goal and proposes to use laser scanning equipment T-scan to complete peripheral skins automatic measurement of the edge contour.According to the acquired measurement data,complete the reconstruction of the geometric model of the peripheral skin edge contour,and then complete the reconstruction of the trimming contour of the flap in combination with the assembly gap,providing a basis for the finishing of the flap,and finally realizing the precise assembly of the flap without margin.The specific research content is as follows:1.Establish a measurement system in the no margin assembly mode of the flap skin.Analyze the seam measurement requirements of the flaps,select appropriate measurement equipment to build an automated measurement system,and develop an automated measurement process for the edge contour of the skin.2.Propose measurement-oriented digital discretization technology of skin edge contour.The research uses CATIA’s secondary development platform CAA to realize the digital discretization of peripheral skin edge contour inspection features,quickly obtain the three-dimensional coordinate information,tangential vector and normal vector information of the discrete points,and provide digital information for path planning.3.Complete the automatic scanning path planning of the skin edge contour.The mathematical model of T-Scan scan line and skin surface is established,combined with the constraints of T-Scan,the intersection is calculated through the software MATLAB,and the intersection point obtained is the measurement point data.Taking the number of measuring points on the outer surface of the skin and the number of measuring points on the edge profile as the objective function,the best position and attitude of the scanner are selected.4.Complete the model reconstruction of the skin edge contour and the mouth cover contour.Establish the outer profile and trimming profile of the skin through the measurement point data obtained from the measurement plan.Take the intersection of the two to obtain the contour curve of the skin edge.Then the contour curve of the mouth cover is obtained,which provides geometric information for the numerical control processing of the mouth cover.