A method for redesigning business workflow for cyber-physical production system

Abstract

The application of a cyber-physical system (CPS) in a production system to improve the efficiency and effectiveness of its operation is called a cyber-physical production system (CPPS). Although a considerable research and development effort has been dedicated to realizing CPPS, less progress has been made to introduce CPPS for small- and medium-sized enterprises (SMEs). This is because replacement of conventional (less-digitalized) production systems with full-scale CPPS will require substantial cost and longer time. Incremental or stepwise changes in production lines and business workflows toward CPPS seem promising rather than drastic digital transformation of a whole factory. In order to help SMEs incrementally develop CPPS in a bottom-up manner, the objective of this paper is to propose a method for redesigning business workflows to connect physical production lines and digital components appropriately. For this purpose, we first propose the framework to understand the hierarchical structure of a CPPS in three levels, i.e., physical and digital components, business workflow, and configuration levels by referring to previous research. Based on this framework, we propose a representation scheme in the form of a sequence diagram to visualize the relationship between the physical production line, business workflows, and digital components. Finally, we define the procedure to redesign a business workflow based on the representation scheme. Through an industrial case study in the die machining industry, we demonstrate the feasibility and effectiveness of the proposed method. We also discuss limitations and the future development direction of the proposed method based on the result of the case study and conclude that the proposed representation scheme and the design procedure are effective for stepwise development of business workflow toward CPPS.