Assembly Process Design Research Articles

Generating the assembly instructions of helicopter subassemblies using the hierarchical pruning strategy and large language model

Assembly instructions are process documents in detail describing the operation steps, materials, tools, fixtures, and assembly sequences in assembly procedures. Due to assembly instructions including numerous contents, and the content being easy for workers to understand, process designers need to spend lots of time thinking and authoring assembly instructions to ensure that workers can complete the assembly task according to the assembly instructions. Focusing on the difficulties of the variety of assembly instructions and the process factors implicit in the standard languages of assembly instructions, a method of assembly instruction generation for helicopter subassemblies is proposed. First, a data representation model of multi-source heterogeneous knowledge and information based on knowledge graphs is designed and established. Then, a hierarchical pruning VF3 algorithm is presented to reuse assembly instructions according to hybrid similarity. Finally, a process factor revision model based on RoBERTa-BiLSTM-CRF is proposed to generate revised assembly instructions. Helicopter subassemblies, which contain 11,240 assembly procedures, are used to evaluate the performance of the method for generating assembly instructions. The proposed method greatly reduces the time cost of assembly instruction authoring and promotes the intelligent development of assembly process design.

Analysis of the influence of assembly deviation and repeated assembly on sealing performance of detachable aviation pipe joint

Detachable pipe joints are an important component of aviation hydraulic systems, and their sealing performance is related to the safety and reliability of the entire machine. This paper focuses on the impact of assembly deviation and repeated assembly on the sealing performance of 35 MPa aviation pipe joints. The sealing performance of pipe joints was quantitatively evaluated using the sealing contact strength theory, and the influence of assembly deviation on sealing performance was studied using the finite element method. Designed a repeated tightening test device for pipe joints and conducted repeated tightening tests. A method for analyzing the initial loss of axial force, usage loss, and friction torque during repeated tightening of pipe joints has been established. Finally, combining experimental data and simulation calculations, the influence of repeated tightening on the sealing contact strength was analyzed. This study provides an analysis method and influencing law for the sealing performance of 35 MPa level detachable aviation pipe joints under assembly deviation and repeated assembly. The research content can provide theoretical guidance for the assembly process design of pipe joints.

Research on digital assembly method of large-caliber optomechanical systems

Developing optomechanical systems with large-aperture output beams is increasingly important for deep space exploration, homeland defense, and modern warfare. However, the assembly process for such systems is becoming more challenging due to their complexity and size. Considering that traditional computer-aided assembly methods for optomechanical systems primarily prioritize debugging and testing, often overlooking the importance of feasibility analysis and verification in the assembly process, this paper presents a digital assembly method for large aperture optomechanical systems that integrates virtual assembly technology with misalignment error detection technology. By combining these two technologies, the proposed method aims to enhance the assembly process by providing a more comprehensive approach that includes feasibility analysis and verification, in addition to debugging and testing. Firstly, virtual assembly technology is utilized to simulate and validate the assembly process design of optomechanical systems. Secondly, a second-order sensitivity matrix method is proposed to achieve higher accuracy in solving misalignment compared to traditional methods. The new method is validated through simulation experiments on an off-axis beam expander system, showing superior solving accuracy compared to traditional approaches. Lastly, an actual assembly and adjustment platform is constructed, and the obtained assembly result exhibits a wavefront aberration RMS value better than 0.016λ (λ=632.8nm).

A question answering system for assembly process of wind turbines based on multi-modal knowledge graph and large language model

In the field of wind power generation, wind turbines serve as the foundation for harnessing electrical energy. However, the assembly process information for wind turbines is typically dispersed among various modalities such as 3D models, natural text, and images in the form of process documents. The difficulty in effectively utilising historical process knowledge hampers the efficiency of assembly process design and subsequently affects production efficiency. To address this issue, this paper constructs a Multi-modal Process Knowledge Graph for Wind Turbines, named MPKG-WT. Additionally, a wind turbine assembly process question-answering system combining multi-modal knowledge graphs with large language models (LLMs) is proposed to enable efficient utilisation of historical assembly process knowledge. The proposed approach achieves outstanding results when compared with other state-of-the-art KBQA methods and recent LLMs using a wind turbine assembly process dataset. The effectiveness of the approach is further validated through a visualised assembly process question-answering system. The research findings demonstrate a significant improvement in assembly process design efficiency.

Development and Simulation Via Flexsim for Kitting Trolley Design of Rear Car Seat Assembly Process

It was discovered that the material retrieval system used for a Sweden brand car seats assembly lines (RB40% and RM60%) in a local seat assembly company was not systematic in its arrangement of the assembly parts and only had a rack trolley that carried all the assembly parts in a poly-box. The workers had to waste time to pre kit the parts prior to assembly process thus could not meet production target. Although kitting trolleys implementation was generally known to help pre-kit earlier at logistic/warehouse department, the fabrication cost and long-term benefit would be affecting company decision to implement kitting trolley in the production line. The study aims to validate kitting trolley implementation efficiency prior to trolley actual fabrication by computer aided simulation. Project started from feasibility study of existing kitting rack trolley in market to conceptual design to detailed design and simulation analysis. Detailed design of the kitting trolley was produced and from the design, time study showed that assembly process per carseat was reduced. Flexsim kitting trolley simulation predicted that the number of car seats produced per day is higher than production quantity target (24 seats per day) for RB40% but still below production target for RB60%. Nonetheless, both showed improvement of hence improving of quantities hence increase company’s productivity and eliminate waste of time.

General prediction model of residual pretightening force of bolt group with one-step and multi-step pretightening and analysis of influencing factors from the perspective of elastic interaction

PurposeThe purpose is to predict the distribution of the residual pretightening force of the bolt group under the action of any initial pretightening force, and to achieve the final residual pretightening force as the target to solve the initial pretightening force value to be applied.Design/methodology/approachBased on the finite element method and the elastic interaction theory between bolt group, this paper establishes a prediction model for the residual pretightening force distribution of bolt group for one-step pretightening and multi-step pretightening of gasketless flange connection systems. In addition, using the general modeling method given in this paper, the prediction model of residual pretightening force of long plate bolt connection system is established, and compared with reference, which fully proves the effectiveness and universality of the general prediction model of residual pretightening force of bolt group.FindingsThe appropriate pretightening sequence, increasing the number of pretightening steps and variable amplitude loading can effectively reduce the influence of elastic interaction and improve the uniformity of residual pretightening force of the bolt group. And the selection of material, number of bolts and connected thickness of bolt connection system also has a great influence on the distribution of residual pretightening force of bolt groups.Originality/valueThe general prediction model for the residual pretightening force of bolt group of connecting structural components considering elastic interaction given in this paper can provide a reference for the design and optimization of the bolt assembly process of the rotor system and the casing system in aero-engine and the prediction of the performance of the connecting system.

Building Community for Participatory Modeling: Network Composition, Trust, and Adaptive Process Design

Complex environmental problems span multiple disciplines and scales of inquiry. Discovering solutions requires inclusive problem-solving spaces. Participatory modeling represents a collaborative research approach that engages stakeholders to co-produce knowledge and problem responses. Scholarship largely features the results of scientific modeling. Lacking are assessments of the nature of participant engagement and collaboration. Our paper offers insights on how to structure, support, and evaluate interactive spaces for participatory modeling, especially during the initial (community building) phase of projects when collaborative culture is established. The Floridan Aquifer Collaborative Engagement for Sustainability (FACETS) convenes stakeholders in the Southeast US from farming, forestry, government, conservation, and academia. We explore network assembly, trust diversity, and iterative process design in FACETS. Through longitudinal reflexive monitoring facilitators appreciate the range of participant needs, integrate feedback into agenda design, and catalyze group reflection.

Design and simulation of fuselage product digital assembly based on DELMIA

As the core process of aircraft manufacturing, fuselage assembly directly affects the performance and quality of the aircraft. However, unreasonable assembly processes, collisions and interferences usually occur in the case of actual assembly. This paper develops the fuselage assembly process design and simulation in a virtual environment established by DELMIA platform. The digital environment consists of products, equipment, workers and other assembly elements. Finally, interference detection and ergonomic analysis are completed through the assembly process simulation. The case indicates that digital assembly process design and simulation technology could reduce the error rate and improve assembly quality.

Knowledge Graph-Based Assembly Resource Knowledge Reuse towards Complex Product Assembly Process

Assembly process designers typically confront the challenge of seeking information out of large volumes of non-structured files with a view to supporting the decision-making to be made. It is a leading concern that embedding data in text documents can hardly be retrieved semantically in order to facilitate decision-making with timely support. For tackling this gap, we propose in this paper a knowledge graph-based approach used to merge and retrieve information decided to be relevant within an engineering context. The proposed approach is to establish a multidimensional integrated assembly resource knowledge graph (ARKG) based on the structure of function-structure-assembly procedure-assembly resource, and this multidimensional integrated structure can well accomplish the retrieval of related knowledge. The upper semantic framework of ARKG is established by the assembly resource ontology model, which is a semantic-type framework involving multiple domains of knowledge to create instantiated data reflecting the full profile of the assembly resource for obtaining structured data of ARKG while avoiding the data redundancy problem. The ARKG method is validated through assembly scenario of the aircraft, and the results show the effectiveness and accuracy of the ARKG used by the assembly process designer in the assembly process design phase for retrieving the target knowledge of the assembly resources.

Research and Development of Digital Assembly Process System for Ultrasonic Transducers

In order to solve the problem of design efficiency of the digital assembly process, the author proposes a research using ultrasonic transducer technology. The main content of this research is to study the ultrasonic transducer elements according to the basic structure of the ultrasonic transducer.Through the study of equivalent circuit of ultrasonic transducer, the model of impedance matching design is constructed. Finally, the feasibility of ultrasonic transducer technology is obtained through experiments. Experimental results show that the transducer multichip structure of the ultrasonic transducer system and the LC matching network circuit can make the AOTF system achieve better results, and the diffraction efficiency is up to more than 70%, which is of great significance to the research and development of the current digital assembly process system. Conclusion. It is proven that the research of ultrasonic transducer technology can meet the needs of digital assembly process design efficiency.

A hierarchical assembly knowledge representation framework and microdevice assembly ontology

Microdevice assembly knowledge is dispersed in different product development phases, such as assembly design, assembly simulation and assembly process, and a lot of essential knowledge is implicit and heterogeneous. It is difficult for researchers and computer-aided systems to share and reuse different assembly knowledge quickly and accurately, leading to inefficient and inaccurate assembly process planning. To integrate and structurally represent the assembly design knowledge, assembly simulation knowledge and assembly process knowledge of microdevice, this paper proposes a hierarchical assembly knowledge representation framework and develops a microdevice assembly ontology. There are four layers in the framework, including the organizational structure, the structural relationship, the assembly accuracy, and the process characteristics. The assembly design knowledge that is integrated involves the basic properties of the assembly object as well as the spatial, mating, and assembly relationship, etc. Assembly simulation knowledge refers to the permissible range of assembly force and contact force. Knowledge of assembly processes comprises assembly sequence and operating method of the part. The microdevice assembly ontology is developed based on METHONTOLOGY, and implemented with Protégé. The corresponding SWRL rules have been established to inference the implicit knowledge in assembly design. An ignition target assembly knowledge model based on the microdevice assembly ontology is constructed. In the assembly task of the ignition target, engineers can quickly and accurately access the required assembly knowledge from the ignition target assembly knowledge model, thus verifying the integrity and validity of the microdevice assembly ontology.

Recent Development of Macrocyclic Compounds as Potential Tool for Cancer Therapy and Diagnosis: A Mini-Review

Macrocyclic compounds can be easily sustained into varied functionality, which has recently famed them as an individual supramolecular entity. Owing to their tenable non-covalent interactions or dynamic covalent bonding, these macrocyclic formulations have contemporaneously inhibited and controlled the progression of infectious diseases and cancers. Macrocyclic supramolecular assemblies have been fabricated for staging the medicinal accuracy of different therapies as well as diagnostic pathways. This mini-review, therefore, focuses on the design of a hierarchical assembly process at the molecular level of chemical composition and presents interesting illustrations of supramolecular assembled structural motifs as new cancer diagnostic and therapeutic options.

Multi-Criterial Algorithm for the Efficient and Ergonomic Manual Assembly Process.

Industry 4.0 introduces smart solutions throughout the company’s supply chain, including manual assembly, where the goal is to ensure shorter work cycle time, increase productivity and quality, while minimizing costs. Following the principles of this paradigm, this paper proposes a digital transformation of the manual assembly process by implementing a multi-criterial algorithm (MCA) for adjusting and configuring a human-centered smart manual assembly workstation to ensure efficient and ergonomic performance of the manual assembly process. The MCA takes into account various influential parameters, such as the anthropometry of the individual worker, gender, complexity of the assembly process, product characteristics, and product structure. The efficiency of the MCA was verified both in the laboratory environment with the time analysis and in the virtual environment using Digital Human Modelling through several ergonomic analyses. The results of the implementation of the MCA on a manual assembly workstation support the digital (re)design of the manual assembly process with the aim of creating an efficient and ergonomically suitable workstation for each worker, thus increasing the productivity and efficiency of the human-centered manual assembly process.

Process knowledge graph modeling techniques and application methods for ship heterogeneous models

In the process design and reuse of marine component products, there are a lot of heterogeneous models, causing the problem that the process knowledge and process design experience contained in them are difficult to express and reuse. Therefore, a process knowledge representation model for ship heterogeneous model is proposed in this paper. Firstly, the multi-element process knowledge graph is constructed, and the heterogeneous ship model is described in a unified way. Then, the multi-strategy ontology mapping method is applied, and the semantic expression between the process knowledge graph and the entity model is realized. Finally, by obtaining implicit semantics based on case-based reasoning and checking the similarity of the matching results, the case knowledge reuse is achieved, to achieve rapid design of the process. This method provides reliable technical support for the design of ship component assembly and welding process, greatly shortens the design cycle, and improves the working efficiency. In addition, taking the double-deck bottom segment of a ship as an example, the process knowledge map of the heterogeneous model is constructed to realize the rapid design of ship process, which shows that the method can effectively acquire the process knowledge in the design case and improve the efficiency and intelligence of knowledge reuse in the process design of the heterogeneous model of a ship.

Optimization of Assembly Process Design about Cable based on MBD in Spacecraft Field

An important part of the low-frequency cable network spacecraft, in order to improve the efficiency of the spacecraft’s low-frequency cable network assembly process, according to the characteristics of the spacecraft cable network, based on the three-dimensional digital design of the spacecraft cable network, the spacecraft based on the three-dimensional model. The design and optimization of the cable network final assembly, a digital cable network final assembly was proposed to achieve the purpose of improving the efficiency and reliability of the cable network final assembly.

Failure prediction in electrical connector assembly: a case in automotive assembly process

Purpose Electrical defects cover an important part of assembly defects and strongly affect the vehicle system performance. Almost 40% of assembly defects are classified as human errors and electrical connection failures represent a significant part of them. Humans still remain a cost-effective solution for the flexible manufacturing systems with increasing product complexity. So, understanding human behaviors is still a challenging task. The purpose of this study is to define, prioritize and validate the critical factors for the complexity of electrical connector plugin process. Design/methodology/approach The critical variables were defined by the expert team members. The required number of measurements and variables were revised resulting preliminary analysis of binary logistic regression. After the revision of measurement plan, the list of critical input variables and the mathematical model were defined. The model has been validated by the fitted values of the residuals (FITS analysis). Findings To the best of the authors’ knowledge, this is one of the limited studies, which defines the critical factors for electrical connection process complexity. Female connector harness length, connector width/height/length differences, operator sense of correct connector matching and ergonomy were defined as the factors with the highest impact on the failure occurrence. The obtained regression equation strongly correlates the failure probability. Practical implications The obtained mathematical model can be used in new model development processes both for the product and assembly process design (ergonomy, accessibility and lay-out). Originality/value The obtained risk factors demonstrated a strong correlation with assembly process complexity and failure rates. The output of this study would be used as an important guide for process (assembly line ergonomy, accessibility and lay-out) and product design in new model development and assembly ramp-up phases.

Digital twin-based smart assembly process design and application framework for complex products and its case study

With rapid advances in new generation information technologies, digital twin (DT), and cyber-physical system, smart assembly has become a core focus for intelligent manufacturing in the fourth industrial evolution. Deep integration between information and physical worlds is a key phase to develop smart assembly process design that bridge the gap between product assembly design and manufacturing. This paper presents a digital twin reference model for smart assembly process design, and proposes an application framework for DT-based smart assembly with three layers. Product assembly station components are detailed in the physical space layer; two main modules, communication connection and data processing, are introduced in the interaction layer; and we discuss working mechanisms of assembly process planning, simulation, predication, and control management in the virtual space layer in detail. A case study shows the proposed approach application for an experimental simplified satellite assembly case using the DT-based assembly application system (DT-AAS) to verify the proposed application framework and method effectiveness.

An approach for assembly process case discovery using multimedia information source

Assembly process design (APD) is a time-consuming and error-prone activity of complex product manufacturing. Assembly process reuse can efficiently improve the process design quality and shorten design cycle. With the rapid development of digital technologies, the information source, which stores reusable information of an existing APD result, becomes multiple and heterogeneous multimedia, e.g. text, 3D model, even images and videos. Currently, most researches focused on using single and structured information source, there has been very little research on how to use multimedia information source. For reusing assembly process, one appropriate way is to capture assembly process case (APC) from existing APD result, retrieve an APC similar to the new assembly and modify the process of retrieved APC to generate assembly process of new assembly. In this paper, a novel approach is proposed to discover assembly process case for assembly process reuse using multimedia information source. First, the integrated representation of APC is constructed, which consists of hierarchical topological structure and sematic assembly process concept. Then, by multimedia dismantling and single-medium parsing, the assembly process information is extracted uniformly from multimedia information source. Moreover, the process similarity between new assembly and APC is calculated to retrieve the reusable APC. The process similarity calculation is comprehensively accomplished from two aspects: applying graph algorithm to calculate the topological structure similarity and applying weighted bipartite graph to calculate the assembly process concepts similarity. Finally, an illustrative case study is performed to analyze the effectiveness of the proposed approach. The result showed that the proposed approach can build an APC library from multimedia information source and help assembly process designers to discover APC for assembly process reuse.

A multimedia case-based reasoning framework for assembly sequence planning

PurposeAssembly sequence planning (ASP) is a crucial job during assembly process design. However, it is still difficult to reuse the existing solution to solve a new ASP problem. In particular, with the rapid development of digital technologies, the reusable assembly information of an existing solution is not concentrated in one multimedia but dispersed in multiple heterogeneous multimedia, e.g. text, three-dimensional graphics, even images and videos. This paper aims to propose a multimedia case (MC)-based reasoning framework to solve ASP by reusing the existing solution whose assembly information is dispersed in multimedia.Design/methodology/approachThe proposed framework is designed with the introduction of the MC. An MC seamlessly integrates the dispersed assembly information of an existing solution. Under the proposed concept and architecture, the assembly information of an existing solution is extracted to build assembly descriptors of multimedia. Therefore, the MC is captured by organizing the assembly descriptors of corresponding multimedia.FindingsBy means of the framework proposed, it is possible to reuse the existing solution whose assembly information is dispersed in multimedia to solve ASP. Moreover, the extraction method of assembly information can flexibly parse most of the multimedia. Finally, the MC has the capability to represent the existing solution by collecting dispersed assembly information.Originality/valueThe proposed framework can discover the similar existing solution and avoid the potential failures confronted in the past so that the feasibility of ASP result can be improved as much as possible.

Robust fixture design of compliant assembly process based on a support vector regression model

Fixtures are used to locate and clamp parts and subassemblies during the compliant assembly process of automotive body parts. As a result, the assembly quality of compliant sheet metal parts is mainly determined by fixture locating layouts and variation sources, such as manufacturing variation of parts and fixture locating variation. This paper proposes a robust fixture design method of the compliant assembly process based on a support vector regression model. Firstly, an assembly variation modeling method of compliant sheet metal parts is discussed during the assembly subprocesses of fixture locating, welding gun clamping, weld finishing, and welding gun releasing. The combined assembly variation model describes a numeric relationship between the assembly variation of key measurement points and all variation sources under a certain fixture locating layout. Further, to solve the difficulty of directly obtaining the parameter model between the assembly variation and fixture design layouts under a certain variation source level, a response surface modeling method based on a support vector regression model is presented. And a whole assembly robust objective function is presented to realize the combining consideration of the whole assembly quality control with different assembly quality controls of different areas. Finally, a taillight bracket assembly is used to demonstrate the robust fixture design method. Results show that the proposed method is feasible and the assembly quality under the robust fixture locating layout has been greatly increased.