Object Scanning Mode Based Composite Product Repair Scheme Design

In aerospace or some other industrial fields,using composite materials always results in low processing accuracy of parts,and due to the complex assembly structure of the products,interference between parts often occurs during assembly processes.As single-piece and small-batch products,assembly is usually completed by repair method in order to reduce costs.However,the repair operation is usually a manual operation and relies on experience.Operators does not have an accurate repair scheme,so they need repeat trial assembly and repair.This process consumes a lot of time and the repair results are uncertain.In order to solve this problem,this paper proposes a design method of product repair scheme based on object scanning model.In the first chapter,the current research situations of feature segmentation method of object scanning model,model expression in virtual assembly,assembly positioning method,interference detection method and repair calculation method at home and abroad are introduced,and the existing problems are analyzed.The research contents and significance of this paper are put forward.The second chapter proposes a method for establishing a hybrid part model for product repair scheme design.According to the model data require,the data conversion interface of CAD model is developed,and an adaptive threshold RANSAC algorithm is proposed to segment the object scanning model.Then the hierarchical representation and data structure of the hybrid part model is constructed,which uses the reference mechanism for data invocation.This lays the foundation for the subsequent product repair program design.In the third chapter,a repair area detection method based on virtual assembly by object scanning model is proposed.Considering the influence of different dimensional accuracy and assembly precision requirements on registration accuracy,a weighted constrained ICP registration method is proposed.The assembly process is established by registering the object scanning model to the CAD model with assembly information.An interference detection method based on signed Hausdorff distance is proposed to quickly judge the interference relationship between parts during assembly process,which is used to determine the repair area and the repair value.The fourth chapter proposes the method for the product repair scheme design and visualization considering the tolerance.The product repair scheme is designed by the analysis of product mountability considering fit tolerance and the analysis of manufacturing precision considering the geometrical tolerance.The repair scheme includes information such as repair parts,repair area and repair value,and visually displaying the repair scheme to guide the actual repair operation effectively.In the fifth chapter,an object scanning model based product repair scheme design system is developed,which realizes the hybrid model data fusion management function,assembly parts positioning function,repair scheme design and visualization function.The system is applied to a satellite truss structure.The sixth chapter summarizes the full paper,analyzes the shortcomings in the research,and puts forward the prospects for the follow-up research work.