Research On Assembly Planning For Complicated Products Considering The Effect Of Assembly Resources

The assembly process is the last step of the product manufacturing; the performance and cost of the product are directly influenced by the assembly of products. Assembly sequence planning is an important part of assembly planning, in assembly process of complex products, the quality of the assembly sequence directly influences the feasibility, cost and the time of the assembly process.In the assembly of complex products, assembly resources such as fixtures are usually needed, and some assembly resources are assembled into the product together with parts. In traditional assembly sequence planning, only parts are taken into consideration, and the derived assembly sequences have the distinct limitations. This thesis investigates an assembly sequences planning approach considering the effects of the assembly resources, according to the practical assembly process of complex products, and shows the necessity of considering the effects of the assembly resources in assembly sequence planning for the complex products. The main work of this thesis is as follows:The main work of this thesis is as follows:1.An assembly sequence planning model is proposed considering the effects of assembly resources: the presentation of the assembly sequences is defined, including the assembly parts, assembly fixtures and auxiliary assembly tools; the assembly interference matrices considering assembly resources are established, and the corresponding conversion and judgment method in assembly sequence planning is proposed; meanwhile, the optimization objectives in assembly sequence planning are discussed and the fitness function is built.2.An assembly sequence planning method based on fireworks algorithm is proposed: some parameters of fireworks algorithm are modified according to the assembly sequence planning problem, the location of fireworks and sparks are redefined, and the location updating method of general sparks and particular ones is improved; the effects of parameters such as initial population, the amount of general sparks and special ones, on the performance of the improved fireworks algorithm in assembly sequence planning are studied through the case study; finally the performance of the fireworks algorithm in assembly sequence planning is verified by contrast to the discrete particle swarm optimization algorithm.3.With the case study of the subassembly of an aircraft wing, the proposed assembly sequence planning approach considering the effect of assembly resources with improved fireworks algorithm is verified, and the superiority of the approach is showed through comparison with the same case without considering the effect of assembly resources.