Enabling Industry 4.0 Service-Oriented Architecture through Digital Twins

A major goal of Industry 4.0 is to increase changeability of production processes, and to reduce the additional cost for individualized products. A service oriented production architecture can enable this goal. However, it demands changes in the software-based systems that compose the different levels of automation in a factory. Additionally, it requires a multitude of data to reflect the demands of service-oriented manufacturing processes. In this paper, we detail the minimal data to be contained in digital twins to enable an Industry 4.0 service-oriented architecture. We use two central Industry 4.0 use cases as drivers for deriving this data. We describe services by detailing their capabilities and their quality of service in terms of time, money and resulting product quality. Using these descriptions, we detail customer's order and the included product to be manufactured. Additionally, we describe challenges of the orchestration process like incompleteness of business processes and detail, how they can be solved using digital twins of the product, the service providers and the plant. Finally, we validate the proposed models by implementing the use cases on two model plants and give an experience report.