Assembly Information Model Research Articles

Assembly feature construction method of equipment mesh model for digital twin workshops

The digital twin workshop is the basic unit for realizing smart manufacturing. Its model is the prerequisite for applying digital twins in workshops. Geometric model assembly is the primary concern in workshop-level digital twin modeling. However, current research lacks sufficient focus on the efficiency and application modes of equipment mesh model assembly features in geometric model assembly, hindering the construction of the workshop-level digital twin model. The equipment-level digital twin model typically only contains assembly information between individual parts and is generally represented by polygonal meshes; the lack of assembly information between equipment models impedes the assembly of the workshop-level digital twin model. To improve the efficiency of workshop-level digital twin modeling and the reusability of the original 3D assembly information, this paper proposes an assembly feature construction method of equipment mesh model for digital twin workshops. A 3D assembly information model is constructed to describe the information related to the equipment geometric model and the assembly features. Then, the assembly features of the equipment mesh model are gradually positioned preliminarily and precisely, achieving precise mapping of the assembly features in the 3D information model to the equipment mesh model and efficient construction of equipment mesh model assembly features. Finally, with the construction and application of equipment mesh model assembly features in an arc welding workshop and storage workshop as an example, the feasibility of the method in improving the modeling efficiency is verified through relevant comparative experiments.

Subassembly Partition of Hull Block Based on Two-Dimensional PSO Algorithm

Subassembly partition is an important process in hull block building as it greatly affects the efficiency and quality of the assembly work. Recently, an experience-based method has been widely applied to the subassembly partition process, which consumes much design time and manpower, thus causing more challenges toward a more highly automated and efficient stage in this process. To shorten the gap, an automated subassembly partition method is presented in this study. First, the assembly information model is defined with essential attributes and topological relations of the parts. Second, an optimization model is established with consideration of a trade-off between the intra-cluster cohesion and cluster number on the premise of satisfying certain constraints. After that, considering the fuzziness and diversity of the subassembly partition problem, a two-dimensional coding discrete particle swarm optimization (PSO) algorithm is developed. Finally, two blocks are demonstrated as instances to verify the proposed method, and the results show that the proposed method is feasible and applicable to the block with a flat structure.

A feature-based assembly information modeling method for complex products’ 3D assembly design

During the assembly design of complex products, the process data management is disordered and the data expression is not standardized, and depends mainly on the experience of technical personnel resulting in a lack of unified data source, low design efficiency, and low automation. This paper proposes a feature-based assembly information model to address these problem, providing standardized original design data for complex product 3D-assembly design. Taking the geometric feature of the mating faces as the study object, the overall structure of complex products and the information requirements of each assembly design stage were analyzed to construct the assembly feature information model. By focusing on the composition and expression form of information in the assembly feature information model, a geometric feature classification criterion applicable to assembly design is presented, and the matching rules of feature pairs, assembly relationship, and assembly constraint instructions are established. Based on these, assembly design information is extracted and expressed in a standardized form. As a validation, the modeling method was conducted on a marine diesel engine cylinder cap as a case study; the performance and applicability of the established rules and the extraction and expression methods were verified through the comparison with the assembly process of the cylinder cap.

Research on Computer-Aided Product Design Technology.

As globalization picks up speed, product innovation—the driving force behind business growth and market competition—becomes increasingly important for advancing product design technology. Computer-aided technology is one of the key components of product design, including issues with scientific analysis, creative thinking, problem-solving, and handling conflicts. Product design technology is gaining more and more attention. Computer-aided technology is now a trendy topic that is being studied by many academics due to the quick growth of computer technology. However, most of them focus on the product information model and solution and do not start from the technical methods and innovation of product design, resulting in many problems in the later solution and information description. Therefore, this paper studies product technology problems based on computer-aided technology and briefly explains the CAI technology-driven technology and the establishment of integrated process model. In this model, the assembly information model diagram is constructed to analyze the conflicts and problems in the assembly model, and then, the CAI-driven integrated innovation technology is called to complete the assembly model design. Conflicts in the assembly design can be minimized by using this paradigm. Finally, the qualitative examination of product design reveals that brainstorming is the process that uses the least amount of energy. The shafting assembly system is reviewed and examined at the same time, and the assembly accuracy accounts for the highest 35 percent of the system, completely indicating the extraordinary impact of computer-aided product design.

Assembly Sequence Planning Based on Hierarchical Model

With the rapid development of intelligent manufacturing technology and ultraprecision machining, assembly technology has attracted more and more attention. Assembly sequence is an important part of assembly process planning. However, assembly sequence is affected by many complex factors, such as the time required to assemble products, the geometric feasibility of assembly sequence, and other factors (tool replacement times and assembly direction change), so it is very challenging. In this paper, an assembly information model based on geometric features of parts is proposed. The model obtains the hierarchical information of the part through the segmentation and feature reconstruction of the part. Based on the influence of the contact surface between parts on the feasible motion domain and assembly domain, the assembly constraint relationship model is established. The objective function is constructed by changing the assembly direction, changing the assembly tools, and evaluating the assembly fit type. The geometrically feasible assembly sequence is optimized to obtain the optimal assembly sequence under the existing conditions. Taking a block, a secondary reducer spindle, and a cylinder as examples, the effectiveness of the method is verified.

Architecture Design of Intelligent Assembly System Based on Complex System

For complex system and product, the virtual and intelligent assembly system can short the designing and manufacturing time effectively, especially for administration of life cycle of product, it can provide the digital models for different period using. In this paper, the intelligent assembly system architecture was designed which includes three-layers, application layer, data layer, and output layer. By using this intelligent assembly system the virtual assembly of complex system products is realized. Then, the framework of intelligent assembly information modelling was designed further which includes geometric information, assembly constraint information, and assembly relationship information. This assembly information model can not only express the connection between assembly parts and assembly relationships, but also provide information sources and acquisition mechanisms for assembly process planning. At last, an example of product assembly is presented which includes 3D models analysis and attribute set for simulation, the intelligent assembly function is accomplished in the end.

Intelligent planning of product assembly sequences based on spatio-temporal semantic knowledge

PurposeThe implied assembly constraints of a computer-aided design (CAD) model (e.g. hierarchical constraints, geometric constraints and topological constraints) represent an important basis for product assembly sequence intelligent planning. Assembly prior knowledge contains factual assembly knowledge and experience assembly knowledge, which are important factors for assembly sequence intelligent planning. This paper aims to improve monotonous assembly sequence planning for a rigid product, intelligent planning of product assembly sequences based on spatio-temporal semantic knowledge is proposed.Design/methodology/approachA spatio-temporal semantic assembly information model is established. The internal data of the CAD model are accessed to extract spatio-temporal semantic assembly information. The knowledge system for assembly sequence intelligent planning is built using an ontology model. The assembly sequence for the sub-assembly and assembly is generated via attribute retrieval and rule reasoning of spatio-temporal semantic knowledge. The optimal assembly sequence is achieved via a fuzzy comprehensive evaluation.FindingsThe proposed spatio-temporal semantic information model and knowledge system can simultaneously express CAD model knowledge and prior knowledge for intelligent planning of product assembly sequences. Attribute retrieval and rule reasoning of spatio-temporal semantic knowledge can be used to generate product assembly sequences.Practical implicationsThe assembly sequence intelligent planning example of linear motor highlights the validity of intelligent planning of product assembly sequences based on spatio-temporal semantic knowledge.Originality/valueThe spatio-temporal semantic information model and knowledge system are built to simultaneously express CAD model knowledge and assembly prior knowledge. The generation algorithm via attribute retrieval and rule reasoning of spatio-temporal semantic knowledge is given for intelligent planning of product assembly sequences in this paper. The proposed method is efficient because of the small search space.

Assembly Information Model Based on Knowledge Graph

There are heterogeneous problems between the CAD model and the assembly process document. In the planning stage of assembly process, these heterogeneous problems can decrease the efficiency of information interaction. Based on knowledge graph, this paper proposes an assembly information model (KGAM) to integrate geometric information from CAD model, non-geometric information and semantic information from assembly process document. KGAM describes the integrated assembly process information as a knowledge graph in the form of “entity-relationship-entity” and “entity-attribute-value”, which can improve the efficiency of information interaction. Taking the trial assembly stage of a certain type of aero-engine compressor rotor component as an example, KGAM is used to get its assembly process knowledge graph. The trial data show the query and update rate of assembly attribute information is improved by more than once. And the query and update rate of assembly semantic information is improved by more than twice. In conclusion, KGAM can solve the heterogeneous problems between the CAD model and the assembly process document and improve the information interaction efficiency.

RETRACTED ARTICLE: Assembly sequence planning method based on particle swarm algorithm

In the paper, PSO algorithm is used to solve the assembly sequence planning problem. According to the analysis and extraction of fixture assembly information, a complete and correct fixture assembly model is established in which PSO algorithm is introduced, including assembly direction matrix, interference matrix, sequence-relation matrix, etc. Taking shorten the assembly time as the optimization goal, the feasible assembly sequences for specific fixture are obtained using PSO algorithm and the optimal assembly sequence is found. The influence of main factors on PSO algorithm is analyzed. With the increase of population, the chance to find the optimal solution increases. When $$\upomega $$ and $$\hbox {c}_{1}$$ increase and $$\hbox {c}_{2}$$ decreases, it is good for global searches of the PSO algorithm. When $$\upomega $$ and $$\hbox {c}_{1}$$ decrease, and $$\hbox {c}_{2}$$ increases, it is good for local searches of the PSO algorithm. In practical applications, the factors should be adjusted according to specific problems.

Study on Concurrent Maintainability Design Based on Pro/INTRALINK

In order to make product maintainable, maintainability engineering encourages sufficient focus on product maintenance at early development stage, and systematic maintainability design throughout product development and design. Maintainability and other life cycle aspects should be concurrently design into product. Integrated maintainability information model is established. Based on product assembly information model, the components of integrated maintainability information model, and how to integrate this model with design process model are discussed respectively. With Pro/INTRALINK as product data management platform, an integrated environment which supports concurrent maintainability design and its establishment steps are explored, including configuring basic environment, establishing master information model, defining and managing design flow, which provide and effective methods for concurrent maintainability design.

Information Modeling and Visualization of Assembly Fat Model for Large-Scale Product

Assembly processes are very complex and hard to setup in one-time for large-scale products. Much assembly information is produced in various assembly processes and such information has not integrated or considered for next assembly processes. This leads to problems of deciding manufacturing tolerance of productions quality in the final assembly process. An object-oriented assembly information model and visualization for VAFM (Virtual Assembly Fat Model), is presented in the paper. The information modeling for assembly processes considers not only geometry data, but also non-geometry information, and those information produced by assembly process evolve, mature and derived during the whole assembly process. The paper presents modeling language based on XML and distributed storage based BSON for assembly object. The visualization of VAFM is also presented.

Assembly unit partitioning for hull structure in shipbuilding

In order to solve the problem that low automatic degree to the block assembly process design will negatively influence construction cycle time and construction quality in shipbuilding, this paper presents a newly developed determination system of assembly units for the hull structure. Firstly, the assembly information model of a hull block which includes the part information and the linkage information between parts is proposed following the structural features and assembly process of the hull structure. Secondly, the assembly relation matrix is established on the basis of the fuzzy assessment rule and then the fuzzy clustering method to analyze partition of assembly units is given out. Thirdly, through analyzing the assembly ability of hull structures, the set of evaluating indexes is founded whose weights are decided by an analytic hierarchy process (AHP). Meanwhile, the model for the assessment is provided by fuzzy synthetic evaluation (FSE) and the comprehensive assessment values of assembly partition schemes can be computed to judge the final optimization scheme. A block assembly is taken as an example to verify the proposed method, and the results show that it is an effective method for solving the partition problem of hull structures.

A Concurrent Design Method for Functional Tolerance and Structure based on the Principle of Decomposition and Reconstitution

To assure feasibility and economy of mechanical product design, tolerance design should be incorporated into conceptual structure design phase. The completion of the evolving procedures from functional requirement to tolerance scheme resolution in the early stage, greatly promotes selection of structure scheme and optimization of cost. The paper provides a concurrent design methodology for functional tolerance using the principle of decomposition and reconstitution using growth design based on functional surfaces. A concurrent design methodology is given, including growth design-supported structure-tolerance design process, assembly information model and TTRS-based tolerance representation model. A recursive design method for function to structure mapping is proposed, and the tolerance design in every step of the iteration is focused on. Geometric variation model is introduced to infer key parts and key features, helping forming tolerance specification while assuring rationality and sufficiency of structure decomposition. In the whole process, structure and tolerance are constrained to each other and an optimization framework is put forward.

An Efficient Method of Assembly Path Planning in Virtual Manufacturing System

With the development of information technology, such as CAD, CAPP and CAM, assembly process, which accounts for large amount of time and cost of manufacturing, to be included in virtual manufacturing system is urgently required. According to the principle that the sequence and path in assembly and disassembly process are reversible, the assembly path can be obtained on the basis of assembly constraints analysis and information model building through optimized and reversed. The method of assembly path planning presented in this paper can effectively reduce computational complexity and improve planning efficiency, whose correctness and efficiency is proven by an application example.

A Method for Designing Assembly Tolerance Networks of Mechanical Assemblies

When designing mechanical assemblies, assembly tolerance design is an important issue which must be seriously considered by designers. Assembly tolerances reflect functional requirements of assembling, which can be used to control assembling qualities and production costs. This paper proposes a new method for designing assembly tolerance networks of mechanical assemblies. The method establishes the assembly structure tree model of an assembly based on its product structure tree model. On this basis, assembly information model and assembly relation model are set up based on polychromatic sets (PS) theory. According to the two models, the systems of location relation equations and interference relation equations are established. Then, using methods of topologically related surfaces (TTRS) theory and variational geometric constraints (VGC) theory, three VGC reasoning matrices are constructed. According to corresponding relations between VGCs and assembly tolerance types, the reasoning matrices of tolerance types are also established by using contour matrices of PS. Finally, an exemplary product is used to construct its assembly tolerance networks and meanwhile to verify the feasibility and effectiveness of the proposed method.

Assembly information modelling and sequences generation algorithm of autobody

This paper attempts to formalise the assembly information of autobody and solve all feasible assembly sequences. In this paper, an assembly information model is built by using polychromatic sets and the mathematic forms of these models are given. The model is described by locating relation equations which express the constrained relationship of locating and displacement interference equations which express the constrained relationship of possible displacement. At first, the assembly information model is used to model the assembly information of autobody; then according to locating relation equations and displacement interference equations, all feasible assembly sequences can be derived. Finally, a case study illustrates the application of the proposed assembly information model. The proposed assembly information model and sequences generation approach is successfully demonstrated by autobody assembly planning, and could facilitate assembly sequence optimisation under a robust and reliable situation.