Research On Methods Of Assembly Sequence Planning For Complex Product

The method of assembly sequence planning (ASP) has been playing the most importantrole in the digital factory technology, and the optimization level of ASP technology has a largeextent determined the quality of the final design of the assembly process and product assembly.Based on the characteristics and problems of ASP in complex product, the method and keytechnologies of ASP has been researched. An assembly sequence planning method was buildedbased on assembly information model, assembly matrix, evaluation system and optimizationmethod in this thesis.Based on analyzing the characteristics and necessity of ASP method, the ASP methodapplied in the digital factory technology and the relationship between ASP and digital factorytheory are introduced in this thesis. The function module of complex product assemblysequence planning method were been established. Then, the structure system of ASP has beenbuild, which has technical support hierarchy, basic data hierarchy, application hierarchy andinteractive hierarchy, and the method and key technologies of ASP are also realized.Establishing the information modeling of ASP in complex product based on model baseddefinition (MBD) method, information modeling technology is divided into three parts of datastructures, information model and data management. To accurately describe the variousinformation types including design, process, assembly and product, the information of datastructures is divided into coordinate system information, physical model information, baselineinformation, annotated corpora information and process attribute information. The assemblyproduct information, assembly process information and assembly resource information areestablished in an assembly information model. In order to improve the information modelingtechnology of MBD, the data management model is divided into design hierarchy, processhierarchy and manufacturing hierarchy. The MBD method can not only realize single productsource data expression, but also realize complex products data expression in the parallelassembly.The method of interference matrix generation technology with bounding box technologyand continuous drawing dynamic interference testing algorithm is proposed. Based on thesetechnologies, the standard orthogonal axes interference matrix and extended interferencematrix are built. Then, the static interference testing and symmetric matrix have been proposed,and the generation technique of connection matrix is realized in this thesis. Combined withstatic interference test and step-by-step interference testing technology, the generationtechnique of support matrix is built. Four matrix generation technology of assembly sequence planning in complex product is realized.The effects of all kind of factors in ASP are analyzed, and the factors are classified aspart-level impact factors and product-level impact factors. And then, the part-level fuzzycomprehensive evaluation is established with the single factor fuzzy evaluation matrix, weightfuzzy comprehensive evaluation and analytic hierarchy process (AHP) method. To establishthe product-level comprehensive evaluation index and calculation method, the objective ofassembly geometry feasibility, assembly body stability, assembly operation convergent andassembly redirection are built. Finally, part-level evaluation index and product-level evaluationindex are combined, and evaluation index and evaluation function are established for solvingASP problems in complex product.In view of the local convergence problem with basic discrete particle swarm optimization(DPSO) in ASP, a hybrid algorithm to solve ASP problem is presented in subassembly. First, achosen strategy of global optimal particle in DPSO is introduced, and then an improved discreteparticle swarm optimization (IDPSO) is proposed for solving ASP problems. Subsequently, amodified evolutionary direction operator (MEDO) is used to accelerate the convergence rate ofIDPSO. The results show that the new hybrid algorithm MEDO-IDPSO is more efficient forsolving ASP problems, with excellent global convergence properties and fast convergence rate.To deal with the problems in assembly sequence planning process, the key technologiesand solving methods are proposed. The information modeling using model based definition(MBD) method of ASP in complex product is established, which is divided into data structures,information model and data management. The generation method of interference matrix,connection matrix and support matrix are established, with the method of bounding boxtechnology and interference testing technology. And the matrix generation method of assemblysequence planning of complex product is realized. Based on the methods of single factor fuzzyevaluation matrix, weight fuzzy comprehensive evaluation and analytic hierarchy process(AHP), evaluation index and evaluation function are established for solving ASP problems incomplex product. The optimization method of hybrid algorithm MEDO-IDPSO is proposed toobtain the optimal assembly sequence with the excellent global convergence properties and fastconvergence rate.