Towards a Product Line Architecture for Digital Twins

Digital twins are a new kind of software systems for which corresponding architectures in different engineering domains have emerged for enabling the efficient interaction of software systems with physical systems to realize cyber-physical systems (CPS). To facilitate the development of digital twins, various software platforms emerged in recent years, which often come with a certain architecture for the developed systems together with a set of domain-specific languages (DSLs) that help domain experts to configure the platform and implement the digital twins. This results in a set of architectures and DSLs which are currently used to realize the various concerns of digital twins. Thus, creating a comprehensive digital twin for a given system requires the combination of several architectures and DSLs, which is challenging as (i) the components of the different architectures have to be combined on a technological level, and (ii) the concerns specified with the different DSLs are developed in isolation which potentially leads to inconsistencies, especially during the evolution of digital twins. To tackle these challenges, we outline our vision of a product line architecture that explicitly specifies the different concerns of digital twins and their alignment on both, the technological level considering the different architectural elements as well as on the language level considering the different language elements. As a result, glue code that is currently required to compose the individual features together into particular digital twin systems is automatically generated. We demonstrate the applicability of this approach by (i) specifying an example product line architecture for selected structural and behavioral concerns of digital twins, and (ii) configuring an existing digital twin based architecture for self-adaptive systems based on this product line architecture by (iii) applying the selected platforms realizing these concerns to a smart room use case. Finally, we discuss expected benefits of the presented approach, such as plug-&-play of digital twin modules, as well as sketch out future work to realize the presented vision.