Modular Control Software Design to Support Mechatronic Variants in IEC 61499

Cyber-Physical Production Systems (CPPSs) consist of deeply intertwined physical and software components. In the last decade, the number of mechatronic components (sensors, actuators, etc.) in a system is increasing enormously to enable more flexible, intelligent production with more support for customization. Mechatronic variability, like different variants of sensors or actuators in the system, directly affects the control software. The standardization of physical interfaces of mechatronic components has provided well-defined plug-and-play interaction. Conversely, software components in the CPPS domain still face the issue of standardizing functionality. Software adaptability often leads engineers to develop control software for new mechatronic variants by just copying and modifying existing software. This leads to multiple and completely separate instances of the control software and a high development and maintenance effort. The core functionality of the control software should be standardized and reused as much as possible to reduce the development effort and improve overall reliability. This paper discusses an approach to standardize core functionality of IEC 61499-based control software. Our design approach encapsulates the process core functionality and defines standard interfaces for interacting with mechatronic variant software components. We evaluate our design approach by comparing it to the traditional clone-and-own approach for an academic case study system, a capping station. Additionally, we assess the impact of adding a new variant in the control software and analyze what changes are needed to keep the same core functionality. When introducing new mechatronic variants in combination with standardized core functionality, our design approach reduces the overall control software variance and maintenance effort.