Design Of Assembly Systems Research Articles

A selection procedure for the design of mixed-model assembly systems considering walking workers and fixed workers

Mixed-model assembly systems are widely used to guarantee higher flexibility, variety and throughput. In such assembly systems, fixed worker (FW) and walking worker (WW) workforce strategies are mainly adopted, influencing tactical and operational decisions with different and sometimes contrasting strengths and weaknesses. Thus, several aspects require a joint investigation to evaluate in which context a WW workforce strategy is preferable to the FW one. In this paper, the effect of assembly and station time variability on WW systems performance is investigated and compared to FW systems through a simulative study. Further, the number of workers and workstations and the effect of the travel time are also analysed. Results show that time variability has an impact on the throughput of both systems, in a different way. Starting from the target throughput and the given time variability among tasks, results derived from data elaboration allow us to propose a decision tree and a selection procedure for choosing between FW and WW systems, highlighting their most proper application conditions. According to the results, the time variability among tasks and the ratio between the number of workers and workstations are the two main drivers influencing the choice between WW and FW strategies.

Assembly process analysis and system design for deep in-situ fidelity corer

The deep in-situ corer is an essential tool for exploring the physical and mechanical behaviours of rocks at varying depths. Corers are multi-part products, encompassing extensive redundant assembly information stemming from the intricate assembly processes and numerous components. Thus, designing assembly systems for corers poses complexity challenges. This paper proposes an automated assembly system design framework, comprising assembly process analysis and system development. The proposed framework offers comprehensive design processes for multi-part product assembly systems, emphasizing managing information amount and complexity during the design phase. Specially, design principles and methods for minimizing information amount are analysed. And the directed graph is utilized to express the assembly information. Building upon this foundation, automated assemblability assessment and assembly process modular clustering is proposed to amalgamate and streamline assembly information, thus reducing design complexity. Leveraging pre-processed assembly information, the sub-functional solutions for assembly system are solved and optimized with AD (Axiomatic Design) and TRIZ (the Theory of Inventive Problem Solving). A case study of the deep-sea gas hydrate corer validated the effectiveness of the proposed methods in reducing information amount and yielding sub-functional solutions, thereby facilitating overall system design realization. Assembly experiments verified the designed system accomplished functional requirements. This study serves as a valuable reference for automated assembly analysis and system development for multi-part products, offering technical insights into developing deep in-situ cores from an assembly perspective.

Utilization of Immersive Virtual Reality as an Interactive Method of Assignment Presentation

Virtual reality is a technology with many possible uses and ways to improve various processes, including the presentation of results. This paper deals with the utilization of virtual reality as a tool for assignment presentation. During the classes of manufacturing and assembly systems design, the conventional form of presentation was replaced with immersive virtual reality, where the students would present their work while wearing the virtual reality headset and walking around the 3D model of their design. The main goal was to test whether this approach had a positive impact on the students’ motivation and engagement in the presentation creation and presenting itself. To test this approach, a small case study took place at the Department of Industrial Engineering, Faculty of Mechanical Engineering at the University of Žilina. In conclusion, the overall responses to this experiment were positive; the majority of the students felt more comfortable while presenting and more motivated to put more effort into their preparation. Wearing a virtual reality headset caused the students not to have to directly face the audience, giving them more confidence while presenting. Additionally, the novelty of the virtual reality technology made the students more engaged in showing their work. There is a plan to integrate the virtual reality presentation as the stable part of this assignment.

Investigating the productivity in different assembly system configurations for a better inclusion of disabled workers

One of the United Nations’ Sustainable Development Goals is focused on decent work and growth which aims to reduce and, finally, remove all barriers for people with a form of diversity like disability. In such a context, manufacturing and production systems should be adapted by adopting specific equipment to help workers with disability while executing jobs according to the type of disability they report. Jobs must be properly planned since disabled workers have physical or cognitive disabilities and specific rights to work. Further, aiming to guarantee a real inclusion of workers with disability production systems should be designed to include these workers in the same working environment as workers without disability. This paper focuses on assembly systems, and it aims to investigate how different designs could impact both the productivity and inclusion of disabled workers. Then, due to the higher variety of products belonging to the same family mixed model assembly systems are considered. For each assembly system design, the daily productivity is calculated by using a simulation approach. Finally, according to the obtained results we provide some considerations about the convenience of adopting parallel flows to guarantee higher inclusion without affecting too much the productivity of the assembly system.

THE DESIGN OF ELEMENTS OF AN ADAPTIVE ASSEMBLY SYSTEM

The paper is an overview of the design of elements of an adaptive assembly system. Furthermore, this paper seeks to address with analysis and evaluation of the elements of the adaptive assembly system. The work presents a taxonomy in the field of adaptive assembly. The core of the work consists of the design of the architecture of individual systems. It is necessary to broaden knowledge about this topic because the designed elements can serve as an overview of this issue. Moreover, at the same time, they can use it in industrial practice. The proposal provides an overview of the elements for possible detailed processing of a specific design of an adaptive assembly system, either when changing an existing assembly system or when designing a new system. To ensure the long-term sustainability of the company's competitive ability, it is necessary to be able to respond flexibly to changes in production and assembly requirements. The issue (theme) is current and was defined based on the finding that there was a demand for the ability to offer multiple product variants and the introduction of new products in shorter and shorter time intervals.

FLEXIBILITY IN ASSEMBLY PLANNING THROUGH PRODUCT DESIGN IN INDUSTRIES

Manufacturing processes and equipment that can handle preconceived and emergency changes with low penalty in time, effort, cost and performance are required in the industries to accelerate introduction of new product, handle breakdown of systems and modification of already existing products. Though there are several attempts on this research, especially in development of equipment capable of handling industrial changes but the results are still not satisfactory. Contributing to achieving a Flexible assembly system. Compensative flexibility Model/Approach was carried out in this research to handle Flexible Assembly system through product design. The model developed performed: generation of assembly sequence, schedule and balancing for assembly planning at the product design stage, extracted product assembles requirements for product design at the conceptual stage to guide the designer; synchronized assembly system and product design and; modularized assembly system and product design. Transportation system of an Assembly system of an engine was simulated using ProModel Simulator and the result was remarkable. Also the design of IC engine using two variance; inline and V IC engines showed remarkable improvement in parts interchangeability and commonality with modularized design; 76% of the parts used in inline engine were also used in the V engine variance. Results from simulation runs with 8 automatic guided vehicle (AGV) in the system were observed, with the average time spent by parts in the system and the average time blocked were significant dropped as number of buffers and AGV were increased; the effect was more pronounced with 8 AGVs and 8 storage buffers in the system. The average (AVG) time blocked with 8 AGV and 1 storage buffer was 56.7 minutes and reduced to 0 minutes when the number of storage buffer increased to 8 with 8 AVGs, the percent reduction was 100 percent while AVG time in the system with one storage buffer was 59.34 minutes and reduced to 4.37 minutes with 8 storage buffers which is 96.9 percent reduction. The variation of number of vehicles and buffers reduced or increased the time component spent in the system. Thus, if correct workstation or assembly system resources are determined and designs are modularised, more articles will be introduced to the market, time to market will reduce, many variances will be produced and there will be reduction in the cost of production. The application of this technique is recommended for processing industry.

Ergonomic Design of an Adaptive Automation Assembly System

Ergonomics is a key factor in the improvement of health and productivity in workplaces. Its use in improving the performance of a manufacturing process and its positive effects on productivity and human performance is drawing the attention of researchers and practitioners in the field of industrial engineering. This paper proposes an ergonomic design approach applied to an innovative prototype of an adaptive automation assembly system (A3S) equipped with Microsoft Kinect™ for real-time adjustment. The system acquires the anthropometric measurements of the operator by means of the 3-D sensing device and changes its layout, arranging the mobile elements accordingly. The aim of this study was to adapt the assembly workstation to the operator dimensions, improving the ergonomics of the workstation and reducing the risks of negative effects on workers’ health and safety. The case study of an assembly operation of a centrifugal electric pump is described to validate the proposed approach. The assembly operation was simulated at a traditional fixed workstation and at the A3S. The shoulder flexion angle during the assembly tasks at the A3S reduced between 18% and 47%. The ergonomic risk assessment confirmed the improvement of the ergonomic conditions and the ergonomic benefits of the A3S.

Exploring the Effects of Perceived Complexity Criteria on Performance Measures of Human–Robot Collaborative Assembly

Abstract The use of Human–Robot Collaboration (HRC) in assembly tasks has gained increasing attention in recent years as it allows for the combination of the flexibility and dexterity of human operators with the repeatability of robots, thus meeting the demands of the current market. However, the performance of these collaborative systems is known to be influenced by various factors, including the complexity perceived by operators. This study aimed to investigate the effects of perceived complexity on the performance measures of HRC assembly. An experimental campaign was conducted in which a sample of skilled operators was instructed to perform six different variants of electronic boards and express a complexity assessment based on a set of assembly complexity criteria. Performance measures such as assembly time, in-process defects, quality control times, offline defects, total defects, and human stress response were monitored. The results of the study showed that the perceived complexity had a significant effect on assembly time, in-process and total defects, and human stress response, while no significant effect was found for offline defects and quality control times. Specifically, product variants perceived as more complex resulted in lower performance measures compared to products perceived as less complex. These findings hold important implications for the design and implementation of HRC assembly systems and suggest that perceived complexity should be taken into consideration to increase HRC performance.

Specifying task allocation in automotive wire harness assembly stations for Human-Robot Collaboration

Wire harness assembly is normally a manual assembly process that poses ergonomic challenges. As a consequence of the rapidly expanding electrification of vehicles and transportation systems, the demand for wire harnesses can be expected to grow radically, further increasing assembly operator challenges. Thus, automating this assembly process is highly prioritised by production engineers. The rapid development of industrial robot technology has enabled more human-robot collaboration possibilities, simplifying the automation of wire harness process tasks. However, successful automation applications involving humans require efficient and safe allocation of tasks between humans and technology. Unfortunately, present assembly system design methods may be obsolete and insufficient in light of the capabilities of emerging automation technologies such as collaborative robots. This paper presents a design and specification methodology for human-centred manufacturing systems and focuses on collaborative assembly operations in complex production systems. A case study on human-robot collaboration provides an application example from a wire-harness collaborative assembly process. The proposed design methodology combines hierarchical task analysis with assessments of cognitive and physical Levels of Automation (LoAc and LoAp). The assessments are then followed by evaluations of the Levels of human-robot Collaboration (LoC) and the Levels of operator Skill requirements (LoSr) respectively. A task allocation matrix supports the identification of possible combinations of automation and collaboration solutions for a human-centred and collaborative wire harness assembly process. System designers and integrators may utilise the design and specification methodology to identify the potential and extent of human-robot collaboration in collaborative manufacturing assembly operations.

Optimal design of automatic assembly system for bolts and nuts in sets

Due to the slow assembly speed, large consumption of compressed air, and low qualification rate, the automatic assembly system for bolts and nuts in sets needs to be optimized urgently. The performance requirements of the system were analyzed, and the evaluation indexes of the system were proposed. Since the efficiency of the system mainly depends on the pneumatic components, the optimization work focuses on the pneumatic circuit. Parameters of the pneumatic circuit and pipeline were obtained through modeling and simulation. After parameter optimization, prototype test results have shown that the assembly speed and qualification rate of the optimized system is increased by 47.83% and 7.77%, respectively, while the air consumption is reduced by 23.39% compared with the original system.

PROJECT-BASED LEARNING FOR ENGINEERING STUDENTS IN THE CONTEXT OF INDUSTRY 4.0: APPLICATION TO AUTOMOTIVE ASSEMBLY SYSTEM

AbstractFourth industrial revolution called Industry 4.0 has radically transformed production systems in manufacturing companies by the integration of emerging technologies. However, manufacturers must overcome several barriers, such as the lack of qualified talent to develop and manage various high-technology systems. Assembly system design aims to define proper assembly line configurations with the optimal performances to overcome increased competitiveness in the market. Nowadays, assembly system design should consider industry 4.0 concepts integration beyond traditional aspects like system balancing and sequencing. In this paper, we introduce a project-based learning approach to teach engineering students assembly system design taking into account industry 4.0 dimension. This project is carried out in collaboration with an industrial partner to design and implement car doors assembly line. The project demonstrated students interest and prepared them better for industry 4.0 era.

Design and Simulation of On-Orbit Assembly System Based on Insect-Inspired Transportation

In response to the requirements of large-scale space in-orbit assembly and the special environment of low gravity in space, this paper proposes a small robot structure with the integration of assembly, connection, and vibration reduction functionalities. Each robot consists of a body and three composite mechanical arms-legs, which can dock and transfer assembly units with the transport spacecraft unit, and also crawl along the edge truss of the assembly unit to a designated location to complete in-orbit assembly while ensuring precision. A theoretical model of robot motion was established for simulation studies, and in the research process, the vibration of the assembly unit was studied, and preliminary adjustments were made to address the vibration issue. The results show that this structure is feasible for in-orbit assembly schemes and has good adjustment ability for flexible vibration.

Contribution to the design of reconfigurable multi-product assembly systems by architecture solutions generation through a new locating-driven approach

Production companies are today faced with increasing product varieties, shortened development times and product life cycles, and decreasing lot sizes. Reconfigurable manufacturing and assembly have been developed as new manufacturing paradigm to face this challenging market environment. However, the aspects of enabling multi-product assembly and operational reconfiguration are rarely addressed. This article presents a new approach, aiming at this research potential: the use of component locating in the center of a new assembly system design method around component locating modules. It is detailed how the use of component locating allows the generation of a system architectures solution space. To support the application of locating strategies, a new model, the precedence-locating graph, is introduced. The approach is described with an illustrative example and the new concept has been tested on an industrial case study in the automotive industry which can only be mentioned partially due to confidentiality issues.

A multi-objective Bi-level leader-follower joint optimization for concurrent design of product family and assembly system

Incorporating interface modularity into the traditional structural–functional modular-based product family architecture (PFA) is of paramount importance for efficient assembly configuration. The structural–functional modularity for PFA only ensures technical system modularity (TSM) with the increasing complexity of assembly and leads to a high redesign cost. In particular, the individual modules and components are assumed to have equal and/or fixed connection values, thereby overlooking the impact of modularity on the assembly configuration. The major challenge for integrating assemblability into a PFA is determining the optimal granularity of modules under the coherent framework of TSM and interface modularity which is often widely different. Responding to the challenge, a decision hierarchy is presented to describe the concurrent decisions of the PFA and assembly configuration through a multi-objective bi-level leader–follower joint optimization (LFJO). The main objective is to maximize profit by ensuring modules with higher commonality and lower interface complexity, which facilitates the design and assembly processes. Consistent with the bi-level optimization, a multi-objective nested bi-level genetic algorithm (M-NBGA) is developed to solve the bi-level LFJO problem efficiently. Numerical examples (i) demonstrate the applicability of the proposed model and algorithm, (ii) manifest the benefit of considering the level of interactions to deal with the product architecture, (iii) validate the contribution of interface modularity in reducing assembly complexity, and (iv) reveal the effect of modular granularity on design and assembly cost.

Design and Implementation of Bolt Feeding Device and Bolt Assembly System

In this paper, a bolt feeding device and a bolt assembly system are designed and manufactured. The bolt feeding device includes: incoming parts, including a material channel, which is used to accommodate bolts; the feeding part includes a silo and a first power part. The silo is equipped with a receiving hole which can be opposite to the material channel. The bolts in the material channel can be moved to the receiving hole. The first power part is used to push the bolts in the receiving hole, so that the head of the bolt and the silo are set in the axial clearance. The above scheme can facilitate the stable pickup of bolts by downstream equipment, and can largely avoid the falling of bolts during the transfer of downstream equipment, so as to facilitate the automatic assembly of bolts.

Study of industrial interactive design system based on virtual reality teaching technology in industrial robot

Abstract Across numerous disciplines, virtual reality (VR) had been used to aid decision-making in training, design, and evaluation processes. Both the educational and industrial groups have contributed to a vast knowledge based on a variety of VR topics during the last two decades. VR has been expanded to industry in recent years, but the majority of its applications do not involve industrial robots. To study the application of VR technology in industrial design, it is better to combine the design activities with computer-integrated manufacturing system and bring new opportunities for the innovation of industrial design. Therefore, in this article, an application of industrial interactive design system based on VR technology in the education domain is explored. First, the function and scheme design of industrial robot assembly and adjustment system are designed, and the model is established. Finally, SolidWorks and 3DsMAX are selected as three-dimensional model development tools. Unity 3D is used as the VR development engine; HTC VIVE is used as VR equipment. The study shows that the design of the machine motion instruction interpreter is effective, and the specific steps of the system to realize real-time control are also given. The feasibility of the system is verified through the analysis of typical applications of industrial robots.

Development and evaluation of design guidelines for cognitive ergonomics in human-robot collaborative assembly systems

Industry 4.0 is the concept used to summarize the ongoing fourth industrial revolution, which is profoundly changing the manufacturing systems and business models all over the world. Collaborative robotics is one of the most promising technologies of Industry 4.0. Human-robot interaction and human-robot collaboration will be crucial for enhancing the operator's work conditions and production performance. In this regard, this enabling technology opens new possibilities but also new challenges. There is no doubt that safety is of primary importance when humans and robots interact in industrial settings. Nevertheless, human factors and cognitive ergonomics (i.e. cognitive workload, usability, trust, acceptance, stress, frustration, perceived enjoyment) are crucial, even if they are often underestimated or ignored. Therefore, this work refers to cognitive ergonomics in the design of human-robot collaborative assembly systems. A set of design guidelines has been developed according to the analysis of the scientific literature. Their effectiveness has been evaluated through multiple experiments based on a laboratory case study where different participants interacted with a low-payload collaborative robotic system for the joint assembly of a manufacturing product. The main assumption to be tested is that it is possible to improve the operator's experience and efficiency by manipulating the system features and interaction patterns according to the proposed design guidelines. Results confirmed that participants improved their cognitive response to human-robot interaction as well as the assembly performance with the enhancement of workstation features and interaction conditions by implementing an increasing number of guidelines.

Ontology-centric industrial requirements validation for aircraft assembly system design

The development of an aircraft industrial system faces the challenge of integrative requirements validation with de-correlated modelling languages and distributed proprietary formats. This paper specifies an ontology-centric industrial requirements validation based on a cognitive digital twin approach, aiming at addressing the potentials of utilizing MBSE ontology integration for different models and leveraging a top level ontology BFO as a semantic core to integrate cross-disciplinary requirement validation, heterogonous models and simulations towards an optimized digital consistency, interoperability and reusability, with an example of such requirements validation presented.

Influence of task time variation in adopting Walking Worker assembly systems: a design approach

Unlike traditional Fixed Worker (FW) assembly systems, in which an operator remains in the same workstation performing repetitive tasks, in the Walking Worker (WW) ones the operators travel along the line stations to produce the finished product. Interestingly, such a configuration enables to achieve a greater level of production volume flexibility, without changing the assembly system layout, parts disposition, and tools assignment. The basic requirement of a WW is to be cross-trained and able to fully assemble the product from beginning to end. The WW travel activity, which increases when the number of stations increases, negatively impacts on the system performance. On the other hand, the possibility to have extra-stations, i.e., a greater number of stations compared with the number of operators, makes the WW system able to dynamically balance the work overload differences between the operators.The aim of this paper is to investigate the effect of stations time variability, typical for example of mixed model assembly lines, on the system productivity, comparing the performance of a WW system and a FW one. A simulative study has been developed, considering as variables the task time coefficient of variation, the travel time, the number of stations, and the number of operators, to analyze when and how the WW system can outperform the FW one. The results show an assembly system design approach that defines the better system to adopt (WW or FW), the number of operators and the number of extra-stations to include, as a function of the considered target productivity and task time variation.

A method to assess design complexity of modular automatic assembly system in design phase

PurposeTo find the system with minimum investment and best quality performance that is capable of producing all of the product variants, assessing the complexity of designing assembly system at the early concept stage is an essential step, which helps and instructs a designer to create a product- and system-oriented assembly solution with the least complexity. The purpose of this paper is to propose a quantifying measurement of complexity in the design of a modular automated assembly system.Design/methodology/approachThe configurable assembly system is becoming a trend, which enables companies to quickly respond to changes caused by different product variants but without a large investment. One of the enabling factors is the availability of modular solutions of assembly modules that can be configured according to different technical requirements. This paper develops a methodology using fuzzy evaluation to calculate the design complexity in the design phase for a modular automatic assembly system. Fuzzy linguistic variables are used to measure the interaction among the influence factors, to deal with the uncertainty of the judgement. The proposed method investigates three matrices to present how the function-based assembly modules, design complexity factors, part attributes and product components, which are regarded as the main influence factors, complicate the construction of a modular assembly system. The design complexity is derived and quantified based on these assessments.FindingsThe proposed approach presents a formal quantification to evaluate the design complexity with regard to a modular assembly system from beginning, which can be identified and used as criteria to indicate the quality of performance and investment cost in advance. A mathematical model based on the fuzzy logic is established to provide both theoretical and practical guidance for the paper. To validate the predictive model, the statistic relationships between the assessed system design complexity, real assembly defect rate and investment cost are estimated based on regression analysis. The application of the presented methodology is demonstrated with regard to a traditional rear drive unit in the automotive industry.Originality/valueThis paper presents a developed method, which addresses the measures of complexity found in the design of a modular assembly system. It would help to run the design process with better resource allocation and cost estimation in a quantitative approach.