Research On Key Technology Of The Virtual Layout And Assembly For Complex Structure Product

How to shorten the development cycle, reduce cost, and improve weapon system engineering ability and level, reduce the combat readiness time (decided by the assembly and examination time in the very great degree), are urgent problems need to be solved for complex weapon system. Reasonable layout and assembly design are not only one of key technique of realization complex weapon product function and solution assembly problems in the design stage, but also an important implementing technology of complex weapon product digital design. Therefore, aim at the complex weapon engineering, it has the important theory significance and practical value to carry on the virtual layout and assembly technology studies for the complex structure product.The layout design of complex structure belongs to packing problem with behavioral constraints, and it is also a complex engineering system problem with inscrutability, uncertainty, and high nonlinearity. The difficulties of solving complex layout problems lie in computational complexity of combinatorial explosion and the complexity of engineering practice. Virtual assembly oriented complex weapon system is a kind of new technology method. Through the present situation analyzing of layout problem solving approach and virtual assembly technology, take the representative complex component in complex weapon system—apparatus cabin of flight vehicle as research object, the constructing principle of virtual layout and assembly system for complex structure product is discussed. Some key technologies for this system are researched, including layout design algorithms, product assembly modeling, and assembly sequence planning, implementing method of assembly simulation. The main characteristics and creative ideas of the dissertation are as follows:(1) Considering the complex structure product design requirements, a framework and functional model of virtual layout and assembly system is built for complex structure productIn the system, the layout design is achieved by constructing algorithm and the product assemblability is tested and evaluated by virtual assembly technology. The enabling tool and main essential technology of system implementation are analyzed and elaborated.(2) Based on the description of complex layout problem under the topic background, a mathematical model of complex layout problem is presented. In question solution process, the real is extended to solution-vector coding in the real-coded genetic algorithm. A solution-vector coded genetic algorithm (SVCGA) is proposed. First, the idea of simulated annealing algorithm (SAA) was inducted to selection operator to control individual diversity. Then different cross and mutating operators were acted on different variables. Moreover, to control the range of searching of the algorithm, a fluctuant scale was multiplied to the variables before they were mutated. Finally, it is necessary for the result of each generation evolution to manage according to the strategy of the elitist preserved. In additional, to test the feasibility and effectively of SVCGA, a two-dimensional and a three-dimensional layout problem with behavioral constraints are introduced and solved by SVCGA. The layout results show SVCGA is feasible and effective.(3) In view of complex layout design characteristic for apparatus cabin of flight vehicle, a new collaborative layout-solving model based on multi-component-agent is presented. The defining and function of each component-agent in model are described in detaiL The solving model conquers defect of traditional methods and is provided with better problem-solving and acclimatization abilities by the collaboration work among component-agents.(4) Analyzing function demand on the assembly model, a feature hierarchy modeling method oriented assembly is presented. In the modeling method, an Assembly Unit (AU) was described for suiting for modeling both single parts and subassemblies and carrying assembly information, while a new product model was presented according to the AU disciplines. For specific the assembly information of different AUs, an integrated object-oriented feature model of AU was introduced. In the models, assembly information contains base-form features and assembly relation between base-form features, assembly features of AU and their attribute. The assembly feature is composed of assembly area and corresponding mating relation. All of the information was organized in terms of the hierarchy structure of class, subclass and instance feature. These measures ensure the coherence of product assembly information in design, reduce the assembly design characteristic recognition difficulty and facilitate the CAD/DFA integration. According to analyzing methods of knowledge representations for products design, a new knowledge representation model based on semantic object is described. And take the apparatus cabin of flight vehicle as the example, the establishment process and the geometry object and the design knowledge integrated method are elaborated based on the UG knowledge model.(5) According to the assembled and disassembled repeatedly characteristic for complex weapon system, the supposition that a product can be assembled then be disassembled is tenable.Some main factors affect the Assembly Sequence Planning (ASP) are analyzed. The assembly feature matrix for ASP is presented and the element of matrix denotes the degree of free (DOF) of assembly feature of a part in reference frame. According to DOF information and correlation information form CAD, the reasoning rules of ASP are established. The computer aided ASP based on knowledge and assembly feature hierarchy model is presented, and optimized.(6) A system structure of virtual assembly simulation based on VRML-JAVA is put forward. The structure makes the display model separate from the assembly model, the virtual assembly separate from the CAD. The formula of expression and transforming of assembly/disassembly motion, the controlling strategy and realization method of virtual assembly, and the impacting examining method in virtual assembly are elaborated. Virtual assembly simulation software found on VRML-JAVA is developed, and is tested by virtual assembly process of ball valve.(7) By analyzing the characteristic of assembly design of complex structure product, some main factors on product structure assemblability and ASP quality are discussed. Based on these factors, the assemblability evaluation methods of product structure and assembly sequence planning are researched. An evaluation method based fuzzy theory and reasonable evaluating model and parameter is ascertained.(8 ) Based on these principles and technique above, a virtual layout and assembly prototype system for complex structure product is established. Some primary verification work is performed in the prototype system by the item of Armament Equipment Researched in Advance. The result indicates virtual layout and assembly principles and technique be feasibility and practicability.