Rapid 3D Assembly Process Planning Considering Typical Process For Aircraft

Three-dimensional assembly process design acts as an essential link that gives full play to three-dimensional digital aircraft development system. With the three-dimensional model of product and resource introduced to the visual environment and interactive task simulation adopted for assembly process planning, this mode not only helps to inspire the designers but also assist with visual assembly orders to instruct field operation. In recent years, three-dimensional assembly process design has shown a number of advantages in aircraft model design though it has also challenged researchers and technical personnel in this field. Three-dimensional process design is more demanding than the conventional model in input and output. The simulation process planning is time-consuming and tedious, which poses an urgent need for relevant theories and methods to standardize process design procedure, improve design efficiency and make sure the product design intent is effectively conveyed to the assembly site. On the basis of typical process element mining and reuse, this paper makes an in-depth study on rapid three-dimensional aircraft assembly process planning. The paper focuses on the following aspects:1) It studies and establishes ontology-based assembly process information integration model. First, the paper analyzes information structure in the mode integrating three-dimensional assembly process design and simulation, and makes successive decomposition and definition of the assembly process. Second, it studies ontology modeling procedures for three-dimensional assembly process design, and provides the method to define assembly object, assembly process, assembly resource and their relations. Finally, based on ontological concepts of assembly process, the paper establishes three-dimensional assembly process information integration framework, specifies the relation among assembly object, process and resource, and provides the foundation for evolution, organization and control of three-dimensional assembly process information.2) It provides methods for typical assembly process element mining and structural description. It starts with analysis of natural semantic composition of assembly order, studies typical element category and general relevance, and on this basis, develops syntactic structure and form for typical assembly process statements. Then, the paper converts assembly process file information into graphic description, and mines typical assembly process elements and their relevance by means of Apriori frequent sub-graph mining. Finally, in view of typical process elements, the paper puts forward the method for parametric modeling of typical assembly process statement, and lays the foundation for standardized and parametric process semantic description.3) It proposes associated drive for typical assembly operation and simulation act scenes. To begin with, in response to the demand for assembly simulation business information, the paper constructs assembly operation semantic model that includes data of assembly connection mode, mating constraint and geometrical elements, and introduces the semantic driving process for three-dimensional assembly simulation business. Next, it studies the information mapping mechanism between typical assembly operation and simulation act, develops parsing rules for assembly operation semantic information, categorizes and defines assembly acts and related parameters to convey assembly operation information from the semantic layer to geometric layer. In the end, it focuses on calculation method for geometrically constrained simulation movement parameters, achieves parametric-driven simulation act scenes by extracting assembly model geometric constraints and calculating movement object parameters, and effectively reduces human-computer interactions in simulation business.4) It presents rapid generating approach for typical element-based visual assembly order. First, attribute information is taken as the indicators to measure the similarity between assembly object and resource to develop the formula to evaluate the similarity among “semantic string”, “type descriptor” and “value”. Then, attribute similarity is used as feature comparison factor to develop method to analyze overall assembly task similarity based on grey relational degree, and allows typical assembly task information comparison and access in order planning process. At last, the paper studies and builds the rapid planning system architecture for typical element-driven assembly orders, provides key steps for order design and typical information reuse, as well as allows rapid planning and generation of visual assembly order.5) Itrealizes rapid assembly order planning and simulation system construction on the w ing assembly unit of an aircraft model, verifies assembly process information modeling, and f unction modules including typical process element and process template, rapid assembly process planning and rapid assembly simulation definition, simulation act play and reverse parsing as well as assembly process file generation. The instance analysis results verify the correctness and feasibility of typical element mining and rapid planning based on the three-di mensional aircraft assembly process information model as proposed in this paper.