Trajectory Planning Method For Fiber Placement Based On Triangle Mesh

With the generalizing use of advanced composite materials in the aerospace industry,AFP(automatic fiber placement)has become an increasingly significant process in modern aerospace technology.In the AFP technology,the design of the layer and the planning of the fiber trajectory are important factors that affect the quality of the composite material.Due to the late start point of the research on AFP technology,current research on the path planning method is still insufficient in China.This paper deals with the surfaces of triangle mesh form and divide such surfaces into several subsurfaces according to mechanic modules,and then provide the method of generalization、densification and evaluation of the fiber path on the meshed subsurfaces.The specific research results of this article are as follows:(1)The history and current situation of AFP and trajectory planning are investigated,and the problems of the existing algorithm for continuous surfaces and the difficulties of the algorithm for triangle mesh are analyzed.(2)The data structure of points,lines and planes are designed according to the topological relationship within the triangle mesh,and the original file of triangle mesh is reconstructed.Based on the parabolic surface fitting method,Gaussian curvature,average curvature,principal curvature and principal curvature direction are calculated on the reconstructed triangle mesh.By analyzing the mechanical relationship between the pressing roller and the mold during the fiber placement process,a method of prezoning the curved surface based on curvature information of the mesh is introduced.(3)The relationship between geodesic curvature and placement failures(folds,fractures)is analyzed,and the generation of a geodesic center path for reducing placement failures is realized on the reconstructed triangle mesh.On the other hand,the angle rules of pavement design are expounded,and the generation of a fixed-angle center path that meets the angle requirements is realized on the mesh.(4)The FMM algorithm is introduced to solve the problem of path densification on the triangle mesh.The method of iteration of the FMM algorithm is justified in order to improve the efficiency of the algorithm;on the other hand,a method of calculationg intercepting subsurfaces instead of the whole surface is proposed to reduce the FMM algorithm redundant calculation.(5)Two kinds of method for calculating the two evaluation indexs for the fiber path considering angle diviation and the rate of gap and overlap respectively are proposed.