Adaptive Assembly System Research Articles

APLAN: open assembly planning framework in FreeCAD

In the latest decade, the consumer’s desire for personalisation has clearly taken of, challenging manufacturers to diversify their product portfolio while maintaining the same (or near) mass-produced prices. As a result, production is nowadays geared towards low volumes with high variety for which adaptive assembly systems are required. Hence, being able to automatically map out the assembly of complex products yields significant strategic advantages over competing manufacturers. Although a wide range of assembly sequencing algorithms have been developed in the past, researchers and companies still experience intellectual and financial thresholds to applying these software packages themselves. Either the algorithms have to be largely re-engineered from scientific literature, or are offered as part of costly commercial CAD software in the form of plugins and add-ons. However, in some cases, the developed source code is made publicly available via online collaboration platforms though in a variety of programming languages and often requiring the cumbersome installation of additional software libraries.Out of these needs, the proposed APLAN module arose: a software framework allowing developers to share their (dis)assembly planning algorithms in a centralised, uniform manner through the open-source 3D parametric modelling software FreeCAD. As impetus, several in-house developed algorithms for determining topological and geometrical (dis)assembly constraints are included as well as an academic (dis)assembly planner. Previously, such algorithms had to be executed via the terminal, after which the extensive liaison, blocking, and AND/OR graphs were outputted as text or static images. Through APLAN, users are now able to inspect and edit these graphs interactively and dynamically. To conclude, this manuscript finally reports on the benchmarking of the aforementioned connection and obstruction detectors, and their academic and industrial application for human-robot collaboration.

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.

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.

Function-based selective and adaptive cyber-physical assembly system for increased quality in optoelectronics industry

Recent advances in smart manufacturing technologies combined with the growing emphasis on zero-defect manufacturing paradigm set a premium on defect mitigation strategies in low-volume production systems. Assemblies for high-tech, high-variety products are becoming more complex, necessitating the need for in-line inspection, prediction, and prevention mechanisms; since the state-of-art end-of-line quality gates are error-prone due to accumulation of variability and errors from heterogeneous sources, originating in upstream process stages. This paper proposes a dynamic function-oriented selective and adaptive assembly based on Cyber-Physical System (CPS) capabilities in order to meet changing product quality standards while enhancing the flexibility of the underlying strategy. A real-case study in optoelectronics industry is used to test and validate the method, highlighting the major benefits of the suggested methodology in terms of final product quality.

Adaptive Automation Assembly Systems in the Industry 4.0 Era: A Reference Framework and Full–Scale Prototype

Industry 4.0 emerged in the last decade as the fourth industrial revolution aiming at reaching greater productivity, digitalization and operational efficiency standard. In this new era, if compared to automated assembly systems, manual assembly systems (MASs) are still characterized by wide flexibility but poor productivity levels. To reach acceptable performances in terms of both productivity and flexibility, higher automation levels are required to increase the skills and capabilities of the human operators with the aim to design next-generation assembly systems having higher levels of adaptivity and collaboration between people and automation/information technology. In the current literature, such systems are called adaptive automation assembly systems (A3Ss). For A3Ss, few design approaches and industrial prototypes are available. This paper, extending a previous contribution by the Authors, expands the lacking research in the field and proposes a general framework guiding toward A3S effective design and validation. The framework is applied to a full-scale prototype, highlighting its features together with the technical- and human-oriented improvements arising from its adoption. Specifically, evidence from this study show a set of benefits from adopting innovative A3Ss in terms of reduction of the assembly cycle time (about 30%) with a consequent increase of the system productivity (about 45%) as well as relevant improvements of ergonomic posture indicators (about 15%). The definition of a general framework for A3S design and validation and the integration of the productivity and ergonomic analysis of such systems are missing in the current literature, representing an element of innovation. Globally, this research paper provides advanced knowledge to guide research, industrial companies and practitioners in switching from traditional to advanced assembly systems in the emerging Industry 4.0 era matching current industrial and market features.

Adaptive assembly systems for enabling agile assembly – Empirical analysis focusing on cognitive worker assistance

Hybrid assembly systems combine the advantages of automated assembly solutions with the cognitive abilities of humans to make assembly more flexible while efficient. Adaptive systems in this context enlarge the scope in which the division of tasks between human and machine can be varied. These systems are an enabling factor for agile assembly since highly situation-aware technologies allow quick reaction in volatile assembly situations. This research focuses on the main opportunities and implementation obstacles of adaptive assembly systems in industrial practice. The results of an empirical study, focusing on cognitive worker assistance, with 132 participants from manufacturing companies, are presented in this paper. Main findings show that the introduction of adaptive worker assistance solutions requires extensive modifications of IT infrastructure. Besides an increase in flexibility, an enlarged potential for the improvement of worker training processes is expected.

Xenon binding by a tight yet adaptive chiral soft capsule

Xenon binding has attracted interest due to the potential for xenon separation and emerging applications in magnetic resonance imaging. Compared to their covalent counterparts, assembled hosts that are able to effectively bind xenon are rare. Here, we report a tight yet soft chiral macrocycle dimeric capsule for efficient and adaptive xenon binding in both crystal form and solution. The chiral bisurea-bisthiourea macrocycle can be easily synthesized in multi-gram scale. Through assembly, the flexible macrocycles are locked in a bowl-shaped conformation and buckled to each other, wrapping up a tight, completely sealed yet adjustable cavity suitable for xenon, with a very high affinity for an assembled host. A slow-exchange process and drastic spectral changes are observed in both 1H and 129Xe NMR. With the easy synthesis, modification and reversible characteristics, we believe the robust yet adaptive assembly system may find applications in xenon sequestration and magnetic resonance imaging-based biosensing.

Design, engineering and testing of an innovative adaptive automation assembly system

PurposeIndustry 4.0 emerged as the Fourth Industrial Revolution aiming at achieving higher levels of operational efficiency, productivity and automation. In this context, manual assembly systems are still characterized by high flexibility and low productivity, if compared to fully automated systems. Therefore, the purpose of this paper is to propose the design, engineering and testing of a prototypal adaptive automation assembly system, including greater levels of automation to complement the skills and capabilities of human workers.Design/methodology/approachA lab experimental field-test is presented comparing the assembly process of a full-scale industrial chiller with traditional and adaptive assembly system.FindingsThe analysis shows relevant benefits coming from the adoption of the adaptive automation assembly system. In particular, the main findings highlight improvements in the assembly cycle time and productivity, as well as reduction of the operator’s body movements.Practical implicationsThe prototype is applied in an Italian mid-size industrial company, confirming its impact in terms of upgrades of the assembly system flexibility and productivity. Thus, the research study proposed in this paper provides valuable knowledge to support companies and industrial practitioners in the shift from traditional to advanced assembly systems matching current industrial and market features.Originality/valueThis paper expands the lacking research on adaptive automation assembly systems design proposing an innovative prototype able to real-time reconfigure its structure according to the product to work, e.g. work cycle, and the operator features.

Towards easy setup of robotic assembly tasks

ABSTRACTThere is a growing need for adaptive robotic assembly systems that are fast to setup and reprogram when new products are introduced. The World Robot Challenge at World Robot Summit 2018 was centered around the challenge of setting up a flexible robotic assembly system aiming at changeover times below 1 day. This paper presents a method for programming robotic assembly tasks that was initiated in connection with the World Robot Challenge that enables fast and easy setup of robotic insertion tasks.We propose to program assembly tasks by demonstration, but instead of using the taught behavior directly, the demonstration is merged with assembly primitives to increase robustness. In contrast to other programming by demonstration approaches, we perform not only one demonstration but a sequence of four sub-demonstrations that are used to extract the desired robot trajectory in addition to parameters for the assembly primitive.The proposed assembly strategy is compared to a standard dynamic movement primitive and experiments show that the proposed assembly strategy increases the robustness towards pose uncertainties and significantly reduces the applied forces during the execution of the assembly task.

Adaptive automation assembly: Identifying system requirements for technical efficiency and worker satisfaction

Manual assembly work systems bring high flexibility but low productivity in comparison to fully automated systems. To increase productivity but maintain flexibility, future systems need to incorporate greater levels of automation which complement or augment the capabilities of the human operators who provide the manual work. Future systems should be designed for social and economic sustainability within fluctuating conditions and for adaptive utilisation of operators’ individual capabilities to maintain levels of productivity and personal satisfaction. To successfully create such systems with greater adaptivity and interactivity between people and technology a comprehensive understanding of design requirements is needed; the current problem is that there is no standard valid framework. The work described in this paper employed a three-component investigation to identify the various key requirements that are needed to form such a design framework for future human-automation assembly systems. This involves separate activities with different methodologies involving literature reviews, surveys and business case analysis to define use case scenarios and requirements for creating adaptive automation assembly system demonstrators. The different methodological approaches and results for all of the three component studies are described, along with conclusions and implications for further research work and for industry in general.

Optimization of selective assembly and adaptive manufacturing by means of cyber-physical system based matching

In high-tech production, companies often deal with the manufacturing of assemblies with quality requirements close to the technological limits. Selective and adaptive production systems are means to cope with this challenge. In this context new measurement technologies and IT-systems offer the opportunity to generate and use real-time quality data along the process chain and to control the production system adaptively. In this article, a holistic matching approach to optimize the performance of selective and adaptive assembly systems is presented and its industrial application within an automotive electric drive assembly is demonstrated.

Integrated quality and production logistics modelling for the design of selective and adaptive assembly systems

Due to the increasing pressure on high precision manufacturing and the development of on-line measurement technologies, selective and adaptive assembly systems have attracted increasing interest in emerging sectors such as micro-production, biomedical and e-mobility industry. Selective assembly allows producing high precision assemblies from low precision components, at the cost of increasing the complexity of the system. This paper presents an integrated quality and production logistics model to profitably manage this trade-off. Results show that improved performance is achieved towards existing solutions, which deal only with quality aspects. The industrial benefits are shown through application to real manufacturing contexts.

A multiagent framework for industrial robotic applications

The paper presents a novel approach toward modeling and governing complex system behavior in flexible and adaptive robotic assembly systems. A fully distributed multiagent approach is implemented for autonomous control. The system is defined at multiple levels of granularity where agents provide services in respect to the current global goal. A decentralized multiagent approach is adopted for reasons of flexibility and fault tolerance embedded in the design phase. To prove the concept a robotic application for intelligent assembly is presented and discussed. It consists of multiple industrial robots equipped with force/torque sensors, 2D and 3D vision systems, automatic tool changers and other sensors and actuators. Through fusion of sensory input and mutual communication agents construct and negotiate an assembly plan and reconfigure respectively.

The cost-saving potentials of assembly systems

In view of growing product diversity and increasingly variable production volumes, the automotive supply industry expects the highest level of variability in plant design. For years, Pfuderer GmbH in Ludwigsburg has been working consistently on the further development of highly adaptive assembly systems which, according to the company, allow their customers to achieve cost savings in the double-digit percentage range.