Digital Twin Technology for Smart Manufacturing and Industry 4.0: Results of a Bibliometric Analysis

Artificial intelligence (AI) and the Internet of Things (IoT), along with blockchain technology, are dominant topics in digitization. Alongside these terms, the term Industry 4.0 is regularly heard, and is familiar to a large part of our society. Far less well known is that science, business and politics are already talking about the next buzzword, the so-called Industry 5.0. But perhaps more about that in an upcoming blog post.

Innovation is seldom the result of a one-sided consideration, a specific circumstance or a specific technology. Rather, innovation is the result of the consideration, investigation and analysis of complex circumstances and interrelationships. Consequently, the mutual interdependencies between business, politics, law and society are regularly reflected in scientific research projects.

Although our name suggests otherwise, we at the Blockchain Research Lab also regularly engage with related topics and technologies. Just like many other scientists, we consider it one of the most important tasks to look beyond our own horizons. This is the only way to identify, understand and explain relevant topics, technologies and developments and to integrate them into our research projects, considerations and publications in the right context.

Blockchain technology, with its applications and the new markets and processes resulting from it, is an essential pillar of digitalization, but not the only one. Consequently, it is important to always analyze it against the background of other technologies and developments in order to be able to adequately assess its opportunities, risks and potential.

In the following, we would like to give you an example in which we conducted a bibliometric literature analysis. The systematic analysis, review and summary of scientific literature and references enables us and our readers to understand topics better and faster.

As part of the STEREO research project funded by the Bundesministerium für Wirtschaft und Energie (BMWi; German Federal Ministry for Economic Affairs and Energy), we have been working on the topic of digital identities. In this context, blockchain technology in the form of so-called self-sovereign identity (SSI) can provide a secure technological basis for specific applications. Nevertheless, it is not the only relevant future technology in this context. In addition to it, there are other promising technologies with high (and probably increasing) relevance for the topic of digital identities. We would like to take a closer look at one of them in this article. It is called Digital Twin and is also referred to as Digitaler Zwilling in German.

Digital Twin technology comprises digital images, replicas or identities of physical systems, objects or assets that can be used, for example, for industrial health monitoring or process optimization and tracking. As part of our article published in Manufacturing Letters, „Digital Twin technology for smart manufacturing and Industry 4.0: A bibliometric analysis of the intellectual structure of the research discourse“, we examined the intellectual discourses of academic research on the topic of digital twin. To this end, 23,419 references from 647 peer-reviewed publications on the topic of Digital Twin were empirically analyzed using bibliometric methods to identify contexts and research streams, from which we can derive insights for our future research projects.

In this context, a “research stream” is a thematic or intellectual aspect within a scientific topic. We identify research streams on the basis of the similarity of the literature references of publications. In simplified terms, the following rule applies: The more identical sources are referenced in articles, the greater their thematic proximity and statistical probability of being located in the same research stream.

The analysis led to seven main research streams, which we briefly describe and summarize below:

1. Digital Twin as a paradigm for the virtual representation of real systems

This discourse comprises about 33% of the identified publications and explains just over 19% of the variance. The variance indicates what percentage of the total scientific discourse is explained by one research stream. In summary, the topics are as follows:

Introduction and description of the Digital Twin concept.
Use of models and data with Digital Twin
Identification of opportunities, benefits, and challenges associated with Digital Twin technology
Thematic focus on health data management and real-time monitoring of aircraft systems (health monitoring)

Significant publications of this research stream include Boschert et al. (2018), Glaessgen & Stargel (2012), Rosen et al. (2015), Tao et al. (2018) and Grieves (2014).

2. Digital Twin for manufacturing processes and human-robot collaboration

This discourse comprises about 20% of the identified publications and explains slightly more than 13% of the variance. In summary, these are the following topics:

Digital Twin driven cyber-physical systems (CPS) in manufacturing and human-robot collaboration (MRC) (e.g. assembly lines, store floors, etc.).
Improving sustainability and monitoring of production processes based on Digital Twin.

Important publications present Caputo et al. (2019), Nikolakis et al. (2019), Tao & Zhang (2017), Zhang et al. (2017) or Park et al. (2019) dar.

3. Cyber-physical systems for the coordination between physical and digital elements

As the third largest research stream, discourse explains about 9% of the variance and comprises about 14% of the identified publications. The following topics in particular are addressed in this regard:

Cyber-physical systems for monitoring and synchronizing data between physical and cyber space.
Digital Twin as a key technology for cyber-physical systems
Relevance of different technologies or methods for cyber-physical systems (e.g. cloud computing, deep learning, AutomationML, Big Data)
Prototypes and feasibility studies in the context of cyber-physical systems

Significant scientific publications of the research stream include Monostori (2014), Wang et al. (2015), Monostori et al. (2016), Negri et al. (2017) or Schroeder et al. (2016).

4. Industry 4.0 for automation in manufacturing and industrial practice

This discourse comprises about 11% of the identified publications and explains 7% of the variance In summary, these are the following topics:

Description of Industrie 4.0, i.e., manufacturing and industrial innovation through the use of smart tools.
Literature analyses on the emergence of Industrie 4.0 and related concepts and topics
Manufacturing systems in the context of Industrie 4.0

Major publications are for example Qi & Tao (2018), Theorin et al. (2017), Sanders et al. (2016) or Liao et al. (2017).

5. Extraction and matching of relationships in the social manufacturing context.

Overall, discourse comprises 8% of the identified publications and explains 7% of the variance. The topics covered are:

Leveraging and transforming large, unstructured data sets to increase the efficiency of manufacturing processes.
Decentralization and socialization of the manufacturing paradigm
Outsourcing, planning, and collaboration in a social manufacturing context.

Significant publications include Liu et al. (2019), Leng et al. (2019), Leng & Jiang (2016) or Leng & Jiang (2016).

6. Advances in computer and communications technology

This discourse includes 5% of the identified publications and explains 4% of the variance. In summary, this topic includes:

Advances and overview of computing and communication technologies, e.g., IoT, cyber-physical systems, Industry 4.0, machine-to-machine (M2M), sustainable manufacturing, edge computing, and image classification with neural networks.

Important publications include Al-Fuqaha et al. (2015), Hehenberger et al. (2016), Stock & Seliger (2016) or Lee et al. (2014).

7. Optimization of geometric variation in spot welding sequences.

This discourse, the smallest in comparison, comprises 4% of the publications studied and explains 4% of the variance. Thematically, it deals with:

Methods, algorithms and simulations for geometry assurance in spot welding sequences or sheet metal assemblies.
Digital Twin for real-time simulation of spot welding sequences

Major publications include Söderberg et al. (2017), Wärmefjord et al. (2010), Tabar et al. (2019) or Liu & Hu (1997).

Finally, the prevalence of each research stream from 1997 to 2019 is shown in the graph below.

Our analysis shows that the scientific environment on the topic of Digital Twin is strongly focused on basic research. It is striking that the current research environment is characterized in particular by publications that have been published within the last five years. This offers exciting approaches for new research projects, such as:

Exploring collaborative or cross-company approaches to digital twin technology based on decentralized infrastructures such as blockchain or process automation using smart contracts. Although the mapping and monitoring of all systems in a supply chain through the use of Digital Twin(s) across different companies as well as legal scopes is initially a complex challenge, its solution could uncover significant efficiency potentials for supply chains as a result.
Harnessing Digital Twin data in the context of academic research or product and system development. Digital Twin data is fundamentally sensitive data, which is why companies have only a limited interest in disclosing it. Consequently, a possible research project could address the question of to what extent and under what conditions information and data could be managed, standardized and made usable by a trustee. In this context, a trustee could equally be represented, for example, by a central company or else a protocol (such as blockchain and smart contracts). Regardless of the choice of trustee, economic incentivization is a key challenge, as the willingness of companies to share their data needs to be increased/stimulated through targeted incentive schemes.

As a reader of the complete study, you will get an overview of essential scientific research streams, significant publications as well as the development of the research environment. This can reduce search costs, reveal approaches for future research, and provide a basic understanding of Digital Twin technology.

The publication of the article in the journal Manufacturing Letters can be found at this link. Access to the article requires a subscription to Elsevier Publishing. If you are interested in a joint exchange or project on the topic with us, we would be happy to hear from you.