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# Designing Smart Products for Industry 4.0 –
An Information Systems Architecture Prototype

Günther Schuh<fnref n="1" />, Max-Ferdinand Stroh<fnref n="1" />, Paul Krüger<fnref n="2" />

**Abstract.** Companies are transforming from transactional sales to providing solutions for their customers. Mostly, smart products, enabling companies to enhance their products by providing smart services to their customers, are a key building block in this transformation. However, the development of a smart product requires many digital skills and knowledge, which regular companies do not have. To facilitate the design and conceptualization of smart products, this paper presents a use-case-based information systems architecture prototype for smart products. Furthermore, the paper features the application and evaluation of the architecture on two different smart product projects. The use of such an architecture as a reference in smart product development serves as a huge advantage and accelerator for inexperienced companies, allowing faster entry into this new field of business.

**Keywords:** industry 5.0; smart products; smart services; digitalization

## 1 Introduction

The digitalization found its way into the manufacturing environment. Even traditional industries such as mechanical engineering are affected by this trend [1]. The products of mechanical engineering, tools and machines, which previously contained only mechanical parts are becoming smart and connected. In other words, they are enhanced with electronic and digital components such as sensors and microprocessors [2]. The result are smart products. They are based on cyber-physical systems and consist of both physical and digital components [1]. They form the foundation of industry 4.0 and by that, the establishment of collaborative networks [3, 4].

Smart products can be used to generate a competitive advantage by improving the customer's benefit [5]. This is based on an analysis of the gathered field data to better understand the customers' behavior and to create new customer-oriented services tailored to their needs. To do so, smart products require one or more information systems for their development and operation to save, process and use the gathered data

<footnote n="1">¹ FIR, Institute for Industrial Management at RWTH Aachen University, Campus-Boulevard 55, 52074 Aachen, Germany
{Guenther.Schuh, Max-Ferdinand.Stroh}@fir.rwth-aachen.de</footnote>

<footnote n="2">² RWTH Aachen University, Templergraben 55, 52064 Aachen, Germany
Paul.Krueger@rwth-aachen.de</footnote>
along their entire lifecycle. However, since most companies in mechanical engineering
are not yet familiar with the use of information systems such as IoT platforms for smart
products, they lack the necessary skills regarding the selection, design and adjustment
of suitable information systems. [2, 5, 6]

To help overcome this knowledge gap and to empower manufacturers of “non-smart” products to develop their own smart products, more specifically the digital components of a smart product, an information systems architecture is needed providing guidance during a smart product development. Current reference architectures do not sufficiently fulfill this need (see section 2). Therefore, this paper aims at providing a first prototype of a use-case based smart products information systems architecture. Based on the user’s selected use-cases it specifies the architectural components necessary for developing a smart product’s information system.

In the beginning, the paper gives a definition of the relevant terms regarding smart
products, information systems and architecture. Afterwards it presents the general
approach for the derivation of the architecture. In section four the authors describe the
requirements regarding the architecture and how the requirements are realized by
elements. In addition to that, the architecture prototype and its components are
described. Subsequently, the resulting architecture is applied and evaluated with two
industry use cases. In the end, a summary and an outlook towards the next steps are
given.

## 2 Background and Related Works

Section two provides the necessary definitions for smart products, information systems and (reference) architectures. Next to that, existing reference architectures and their suitability for smart products are evaluated.

### 2.1 Smart Products in Mechanical Engineering

Smart products are in the limelight of Industry 4.0 and one of the main topics among the smart factory, smart logistic, smart development and others [6]. Based on HICKING'S definition ([1, 7]) the authors define a smart product as "a product, which consists of both a physical and a digital component. They create value for both, its user (mostly the customer) as well as its manufacturer. For users a smart product's main added value is to provide smart services. For the manufacturer it is the opportunity to learn from its newly generated usage data". Smart services are a data based combination of both digital and physical services provided by smart products [8].

In mechanical engineering there are two main fields of application for smart products: The use of smart products in the own production and the sale of smart products as well as accompanying services [9]. Examples of smart products in mechanical engineering are software applications for a mobile steering of machines or connected machines which are capable of gathering and analyzing production data in real-time [10].
## 2.2 Information Systems for Smart Products

Smart products require information systems to handle the gathered data. An information system is a socio-technical system which comprises human and machine components or subsystems [11, 12]. It supports gathering, structuring, processing, provision, communication and usage of data [11]. Regarding smart products, the information system enables the networking with other products or systems as well as data processing. Thus, it improves the customer understanding and is the basis to offer value-adding smart services to the customer [5, 6]. Such an information system can be understood as a so called “product cloud” as coined by PORTER & HEPPELMANN [2, 5]. They can be realized through different digital solutions such as IoT platforms, PLM-Systems, or a self-developed software system.

## 2.3 Architectures and their Reference Character

An architecture is the mapping of functions to elements as well as the description of the element's relationships among each other. The elements are arranged in a structure and create a benefit as a whole [13, 14]. They are used to describe existing systems but are also used for the development and improvement of new systems. Therefore, an information system architecture can be defined as a structured arrangement of an information system's elements and their relationships to each other [15-18].

Some generic architectures are also used as a guidance for the development of concrete product or product line architectures by providing the definitions of relevant terminology, components and structures of the system [19]. In this case, the developed architecture can as a prototype of a reference architecture. A reference architecture describes an architecture which comprises the knowledge about how a concrete architecture for a specific use case must be designed [20]. A generic reference architecture can be used to derive concrete architectures for specific products or product lines [20].

## 2.4 Existing Reference Architectures

A variety of architectures, which describe and explain the structure and the components of smart products, including their information systems, exist in scientific literature. They can be roughly separated into industry-driven architectures, as well as practical, or software-driven architectures. Among the most common industry-driven architectures are the Technology Stack from PORTER & HEPPELMANN, the Industrial Internet Reference Architecture (IIRA), the Reference Architecture Model Industry 4.0 (RAMI 4.0) and ISO 30141 [2, 19, 21, 22]. Compared to the software-driven Microsoft Azure IoT Reference Architecture, the Amazon AWS well architected framework and the concept of the ADAMOS IoT-Platform [23-27].

These architectures provide guidance for the development and design of IoT and Industry 4.0 applications in general. Nevertheless, existing architectures do not consider the specific requirements and use cases of smart products in mechanical
engineering. They also do not include Smart Services. Therefore, a high adjustment effort is inevitable when these architectures are applied in mechanical engineering. To close this gap between the existing architectures, the aim of this research is to provide a practical, use-case based architecture, to allow an intuitive approach to the development of smart products.

## 3 Description of the Methodology

The approach to create the presented architecture follows the method of KRCMAR ET AL. [28]. This approach is technology-independent and creates an architecture based on the system requirements. Fig. 1 gives an overview of the approach.

<figure><img src="image_2.png" /><figcaption>Fig. 1. Research Methodology applied in this paper</figcaption></figure>

In the first step, an extensive requirement analysis is conducted. The requirement analysis is based on 12 scientifically derived use cases from HICKING which cover the most common applications of smart products in mechanical engineering [29]. Furthermore, the use cases were complemented by a literature review as well as several interviews and workshops with smart product experts [29–36]. Secondly, all requirements were matched with the 12 use cases, allowing a prioritization of the requirements. The prioritization is used to categorize the requirements into generic and optional requirements. Generic requirements are particularly important for most of the use cases whereas optional requirements are relevant for only a few use cases. The result of this step is a structured requirements list. In the following step, all the requirements of the structured requirements list are transferred into architecture elements and their relationships are described. The identified elements are clustered into modules and form the architecture prototype, as result of the fourth step.

## 4 Derived Smart Product Reference Architecture Prototype

This chapter presents the results of the methodology. In the beginning, the requirements are described. Then the requirements are transferred into elements and modules of the information system, which are presented afterwards.

### 4.1 Structured List of Requirements

As discussed previously, 12 use cases, a literature review and several interviews were used to capture all requirements of the information system for smart products in mechanical engineering. In total, 112 different requirements were identified. For a
better understanding, they were grouped and summarized into eight different requirement categories. Table 1 gives an overview of the requirement categories.

<table><caption>**Table 1.** Description of the requirement groups</caption><thead><tr><td>Requirement group</td><td>Description</td></tr></thead><tbody><tr><td>Preparation &amp; Development</td><td>Includes all requirements that must be met before the operation of the smart product and the information system starts.</td></tr><tr><td>Networking</td><td>Comprises all requirements regarding data transmission and connection of smart products.</td></tr><tr><td>Product Usage &amp; Interaction</td><td>Describes the requirements that must be met during the usage of the smart product by the customer.</td></tr><tr><td>Data Gathering</td><td>Collects all requirements about the data gathering in the smart product, which is the foundation for data analysis and smart services.</td></tr><tr><td>Data Storage &amp; Provision</td><td>Includes the requirements regarding the short- and long-term storage of data as well as the provision of gathered, stored and analyzed data.</td></tr><tr><td>Data Processing</td><td>Describes the requirements about the analysis of gathered and stored data due to statistical evaluations or other methods with the goal of creating new information and knowledge.</td></tr><tr><td>Smart Services</td><td>Collects all requirements regarding the services which accompany the physical product and which are based on the gathered data and created knowledge due to data.</td></tr><tr><td>Data Security &amp; Access</td><td>Comprises all requirements about the security, the protection from unauthorized access and other threats.</td></tr></tbody></table>

Subsequently, the requirements were linked to the 12 use cases and categorized as generic and optional requirements. In total, 25 generic requirements were identified, which are particularly important for the majority of the use cases. Some example requirements are: “Gather condition data”, “Enable networking” or “Analyze data”.

## 4.2 Derived Architecture Elements

The requirements of the structured requirements list are transferred into architecture elements. An element can be interpreted as a component of the information system for smart products. The guiding principle for the transfer from requirements to elements was the separation of concern [37]. According to this principle, an element should form a logically self-contained unit and fulfil one function of the system [37, 38]. This means that every requirement is linked to exactly one element. However, an element can realize several requirements. If an element realizes a generic requirement, it automatically becomes a generic element. If an element realizes optional requirements only, it is an optional element.

The optimal realization of the requirements by elements was identified in an iterative process. The result is a list of 49 elements which realize all identified requirements.
Similar to the requirements, the elements can be grouped and summarized into groups, the so called modules. Table 2 shows the identified 12 modules.

Like the requirements, the elements were also linked to the 12 use cases. Furthermore, the functional relationships between the elements were examined. These two steps make it possible to derive a specific architecture for smart products in mechanical engineering for each use case, which includes the interdependency of the elements of the information system.

<table><caption>**Table 2.** Description of the modules</caption><thead><tr><td>Module</td><td>Description</td></tr></thead><tbody><tr><td>Supporting Elements</td><td>Includes all elements which support the general development and improvement of the information system but have no direct influence on the functionalities or the customer experience.</td></tr><tr><td>Connectivity</td><td>Contains all elements which ensure the connectivity of the smart product with other objects or systems.</td></tr><tr><td>Data Gathering</td><td>Comprises all elements which determine what data needs to be captured and how.</td></tr><tr><td>Data Storage</td><td>Includes all elements regarding the storage of gathered and processed data.</td></tr><tr><td>Data Provision</td><td>Includes all elements regarding the provision of gathered, processed and stored data.</td></tr><tr><td>Data Analysis</td><td>Comprises all elements which enable the information system to process the gathered or stored data.</td></tr><tr><td>Product Usage</td><td>Contains all elements which have a direct impact on the product settings and which determine the product's interaction with the customer.</td></tr><tr><td>Usage Analysis</td><td>Comprises all elements which enable the tracking, processing and storage of usage data.</td></tr><tr><td>Documentation</td><td>Includes all elements which enable the storage of gathered and processed data in structured and standardized reports.</td></tr><tr><td>Sales</td><td>Contains all elements that support the sales department to handle existing services and to sell new services.</td></tr><tr><td>Smart Services</td><td>Comprises all elements with a direct impact on the customer benefit and all elements for which the customer pays.</td></tr><tr><td>Data Security and Access</td><td>Includes all elements which secure the system's security and protect it from unauthorized access and other threats.</td></tr></tbody></table>

## 4.3 Architecture Visualization

The visualization and presentation of the results is of vital importance for the acceptance and application of an architecture. The results must be presented comprehensible in a way, which allows an unproblematic use in practice. For this, a presentation with different viewpoints is often helpful. A viewpoint highlights certain
aspects of a system and allows a contemplation from a specific perspective, e.g. a
functional or a technical perspective.[39].

The presented architecture is composed of the 12 modules with the 49 elements from Section 4.2. The architecture prototype is displayed in the functional view. The functional view describes the elements, their function and the modules interdependencies. The relationships between the elements are not shown to enhance legibility. Fig. 2 shows the developed architecture prototype.

<figure><img src="image_3.png" /><figcaption>**Fig. 2.** The functional view of the information system architecture</figcaption></figure>

The functional view is displayed as a house visually emphasizing the character of an
architecture. The interdependencies of the modules are displayed with connections
between the blocks. In addition, there are three building blocks, which influence most
of the other elements. These are the Supporting Elements, Connectivity and Data
Security & Access. They form the foundation of the architecture and are displayed at
the bottom of the figure.

In the center of the architecture are the elements handling the data. The interpretation
of data forms the smart component of a smart product and enables Smart Services
providing a benefit for the customer. The data originates mainly in the product use,
handled by the homonymous module. The produced data is gathered, stored, analyzed and managed by the modules Data Gathering, Data Storage and Data Analysis. This is often realized by a middleware application that handles the data provision between different subsystems. The results of the data processing need to be documented, which is performed by the element Documentation. To determine individual customer needs and to tailor customer-centric Smart Services, the usage of each product must be captured and assessed. This is the function of the module Usage Analysis. The resulting insights can then be used to create new Services and thus to increase profit. For this, the information system needs to support the Sales department with billing and further customer service, which is executed by the module Sales.

If all these modules work together, a company has the capability to offer value-
adding Smart Services to the customer. This module is displayed in the top. Like the
roof of a house, this module cannot be realized without the support of the other modules.

The architecture prototype presented in this paper can be used as a reference to derive
a concrete product or product line architecture for a specific use case of smart products.
This implies a selection and adaption of the containing elements. The first step is to
select one of the 12 use cases from HICKING. Based on this, the relevant elements to
realize the use case can be identified and eventually customized and detailed. Most use
cases do not require all elements but can be realized with a reduced selection of
elements. This fulfills the initially mentioned intention of the architecture to identify
the architectural components necessary for realizing certain smart product use cases.

5 Application of the Architecture and Discussion of the Results

The purpose of the architecture prototype is to support the derivation of specific architectures for use cases. To verify the results, the architecture was applied to two industry use cases. For the verification process, companies already offering smart products were selected. During the verification process, the developed architecture was applied to the industry use cases, which was then compared to the architecture that was developed in reality, without the architecture prototype. This allows the comparison of the use case's existing architecture and the architecture derived by the presented method.

The developed architecture was applied to the two industry use cases, before
familiarizing with the actual realization. This led to the a-priori-architecture.
Afterwards, the a-priori-architecture was compared with the actual, existing
architecture of the use case. By doing this, the authors examined whether the method
supplies useful results and whether the a-priori-architecture determined by the method
resembles the actual solution realized in the use case.

The first company is a German SME and founded in 2012. They develop innovative construction machines which produce hoses that are filled with sand or other soil materials. For their smart machines, the company provides a subscription model, which is handled by an information system. The comparison of both architectures is shown in Fig. 3.
<figure><img src="image_4.png" /><figcaption>**Fig. 3.** Comparison of the a-priori-architecture and the existing architecture of the first use case "construction machine"</figcaption></figure>

The a-priori-architecture shows a high degree of conformity with the company's actual architecture. Out of the 36 selected elements in the a-priori-architecture, only three were not used in the existing architecture. These are product adjustment, product description and customer service. Two other elements were added. These are error reports and historic scenarios.

The second company is a SME, which is a specialist in the glass industry and provides services for glass processing machines since more than 25 years. The objective of their smart product is to increase the product availability by enabling a product monitoring and a notification about occurring issues. For this task, the company requires an information system. The comparison of the a-priori-architecture and the existing architecture is shown in Fig. 4.

<figure><img src="image_5.png" /><figcaption>**Fig. 4.** Comparison of the a-priori-architecture and the existing architecture of the second use-case "glass machine"</figcaption></figure>
Here too, the a-priori-architecture shows a high degree of conformity with the company's actual architecture. Out of the 27 selected elements in the a-priori-architecture, 26 were used in the existing architecture. Only the element production improvement was not used in the existing architecture. Three other elements were added. These are user interface, KPI visualization and mobile access & steering.

The high degree of conformity for both use cases is a promising indicator for the accuracy of the derived architecture prototype. Only small adjustments were needed. Based on the first applications, the architecture prototype presented in this paper appear to be of high accuracy in covering use cases in mechanical engineering.

However, further applications of this architecture are necessary to confirm the results in other companies and to assess its usability. Furthermore, the architecture has not yet been applied on companies from the beginning of a smart product development project. For this, further research with the collaboration of companies from mechanical engineering is necessary. Besides that, the architecture will be displayed in other views as explained in chapter 4 to realize its full potential. These views need to be detailed and will be shown in future publications.

## 6 Conclusion

This paper introduces an information system architecture prototype for smart products in mechanical engineering. In the beginning, the authors defined the relevant terms regarding smart products, their information systems and architecture. Based on the approach of KRCMAR ET AL., the requirements related to the information system of smart products were collected. In accordance with the principle of separation of concern, these requirements were transferred into elements and modules which realize the identified requirements. The elements form the resulting architecture prototype, which is shown in a functional view. The functional view describes the elements, their function and their interdependencies. In the end, the architecture's application to two industry use-cases is shown in two industry use-cases.

**Acknowledgements.** The Cornet project 303 EN of the Research Association FIR e. V. at the RWTH Aachen University is funded via the AiF within the framework of the programme for the funding of cooperative industrial research (IGF) by the Federal Ministry for Economic Affairs and Climate Action (BMWK) on the basis of a decision by the German Bundestag.

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