A method for supporting the transformation of an existing production system with its integrated Enterprise Information Systems (EISs) into a Cyber Physical Production System (CPPS)

Highlights

• A meta-model for formalizing the object classes that constitute CPPSs, with a particular emphasis on involved EIS.

• A method for supporting the transformation of an existing production system with its integrated EIS into a CPPS.

• Gap analysis between the As-Is system and the To-Be system.

• A checking matrix to immediately visualize what should be improved to move towards CPPS.

Abstract

Cyber-Physical Systems (CPSs) combine the use of components from the physical and the digital worlds in a synergistic way. Cyber-Physical Production Systems (CPPSs), essential in Industry 4.0, result from the application of CPS principles to production environments. To promote the widespread implementation of CPPSs, it is necessary to study how to transform an existing production system with its integrated Enterprise Information Systems (EISs) into a CPPS. This is a very broad question and the scope of this work is limited to the concept development stage. The purpose of the paper is twofold: (1) to elaborate a meta-model for formalizing the elements that constitute CPPSs, with a particular emphasis on the involved EISs, and (2) to propose a method for supporting the transformation of an existing production system with its integrated EISs into a CPPS. Firstly, a literature review on the transformation methods towards CPPSs is carried out. It concludes that existing studies do not consider all aspects of CPPSs, especially its EISs, and that there is a lack of a method that analyzes the gap between the As-Is system and the To-Be system. As a result, a meta-model describing the main object classes that constitute CPPSs and the interrelationships among these classes, is proposed. Next, a method based on the meta-model is proposed to support the transformation into a CPPS. It provides a checking matrix to immediately visualize which improvement actions in the As-Is system are required. Furthermore, a case study illustrating the use of the method is presented. Finally, the contributions of the study are summarized and future work is highlighted.

Introduction

The manufacturing industry is facing challenging trends, such as highly customized products, increasing product complexity and shorter product lifecycles. Cyber Physical Systems (CPSs), which are characterized by a tight interaction of computational and physical elements to provide intelligence, responsiveness and adaptation (Leitão et al., 2016), are part of the solution for tackling the growing challenges that manufacturing industries are facing. The specific application of CPSs to production environments results in Cyber-Physical Production Systems (CPPSs).

Although CPPSs can bring many benefits, the real-scale implementation of CPPSs in industrial practices is still in its infancy due to the legacy barrier (Calderón Godoy and González Pérez, 2018). Actually, enterprises are still conservative in adopting new solutions, especially because of the lack of roadmaps and methodologies that support the transformation from legacy systems to a CPPS. Therefore, a comprehensive transformation methodology is required to support industries to move from their legacy systems towards a CPPS.

Transformation approaches are being proposed in recent years, but not many. These approaches either focused on the retrofit of specific elements of CPPSs (i.e., retrofit of machine tools (Lins et al., 2017)) without considering all elements of CPPSs especially Enterprise Information Systems (EISs), or focused on improving some performance of legacy systems without full transformation into CPPSs, as in (Calderón Godoy and González Pérez, 2018; Orellana and Torres, 2019; Di Carlo et al., 2021). Therefore, to the best of the authors’ knowledge, no comprehensive methodologies on the transformation from legacy systems to CPPSs have been proposed so far.

Consequently, transformation of legacy systems into CPPSs is an emerging topic that is growing rapidly and deserves more attention. However, this is a very broad topic and includes overwhelming and complex tasks that cannot be simply handled by this paper. While the ultimate goal is to develop a comprehensive methodology for transforming legacy systems into CPPSs, at the moment the paper is a preliminary study positioned at the concept development stage which attempts to provide a partial contribution to this broad topic. The contribution of the paper consists of a meta-model defining all necessary elements of a CPPS, with a particular emphasis on involved EISs, and a method for transforming an existing production system with its integrated EISs into a CPPS to guide industry practitioners in visualizing which elements need to be added and modified to become a real CPPS.

The rest of the paper is organized as follows: In Section 2, we propose the definition of CPPSs and further elaborate the research problem, scope and objective. Section 3 presents the related works of the transformation methods into CPPSs. Section 4 presents the meta-model of CPPSs and Section 5 presents the method for the transformation into a CPPS. Section 6 illustrates the use of this method with a case study. Section 7 concludes the paper by synthesizing the contribution and indicating future research directions.