Modularization Technique to Support Software Variability in Cyber-Physical Production Systems

Industries still have problems managing and organizing control software variants for different machine processes in Cyber-Physical Production Systems (CPPSs). They still rely mostly on clone-and-own approaches to create new control software variants when introducing new process variability in reaction to customers' requirements. This approach not only results in code duplication but over time particularly makes it more difficult to maintain and evolve the software. Due to a lack of modularization, this approach also often results in unnecessary code in delivered software, locked by parameters, which can have a further negative effect on maintenance. In this paper, we discuss modularization approaches to organize control software in CPPSs. Specifically, for IEC 61499-based control software, we propose the combination of explicit variants described in 150% modules, standardized interfaces, and separation of concerns. We discuss how our approach could help industry to decrease the effort for new projects and at the same time get a better overview of the product and process variability of their CPPSs.