Digital Assembly Process Planning And Simulation Of Turbine

Digital assembly process planning and simulation can effectively shorten the cycle of assembly design and production, which is important to rapidly development of product. Digital assembly process planning is active research area of CAD/CAM in recent years, however so far there is not practical system for product assemblies with complex structure. Based on deep analysis of current research literature, this paper proposes solutions to several key techniques of digital assembly process planning and simulation and develops a prototype system for turbine.This dissertation studies assembly model and its construction methods for assembly process planning and simulation. Chain modeling method is proposed to provide a model for the static assembly simulation, parameters is used to represent the tolerance and geometric tolerance. Level connection graph model which combines hierarchical and connective relation is proposed to represent assembly structure to provide the conditions for producing the assembly sequences using cut-set method. Assembly constraint models are proposed to simplify the level connection diagram model, and a assembly rules database is established to provide data for the knowledge-based Petri net.This dissertation studies assembly process planning method based on knowledge-based Petri net (KPN), which generates optimum assembly sequence from level connection graph model automatically. The assembly level AND/OR graph is generated by cut-set calculation of the level connection graph. With the AND/OR graph, KPN is built. By running the KPN,optimum assembly process will be obtained.This dissertation studies the assembly process simulation for assembly production process. A method of static assembly simulation is proposed, which is based on the parameter-driven theory and an algorithm measuring the minimum distance between two instances. Bounding theory is used to achieve interference analysis. Based on coordinate transformation and optimum assembly sequence, assembly animation is be made to simulate the assembly process.Based on the UG platform the system is realized, including the assembly process planning and assembly simulation. It can complete the formation and management of the assembly process, data management and maintenance of assembly, the gap analysis and interference analysis, assembly process simulation and other functions, a turbine rotor is used as example to test the system.