With the Industry 4.0 initiative, actors of complex systems are typically represented by their Digital Twin (1-to-1 representation of its Real Twin, especially in terms of semantics, structure, behavior, and interaction). One of the biggest drivers in the industrialization of Digital Twins and IoT is the Asset Administration Shell (AAS), aiming to standardize access and communication in the Industry 4.0 landscape. While the technology benefits are promising, they must be accessible to each stakeholder in a simplified manner, easing the automation and thus use and maintenance of complex systems.
Process-driven approach
The process-driven approach describes the modeling and implementation of Digital Twins services through processes.
Currently, the implementation of AAS-based Digital Twins is complex and requires a deep understanding of the AAS-metamodel. Here, process modeling languages such as BPMN2.0 or Petri Nets might serve as a simplified tool to visually program and observe a Digital Twin in the Industry 4.0 landscape while providing a common modeling language for the behavioral model of the Digital Twin.
Figure 2: Process modeling of Digital Twins behavior on different hierarchical levels based on the BPMN 2.0 standard, illustrated for an exemplary logging process in Forestry 4.0. Left: Visualization of the high-level choreographed logging process. Top-right: Visualization of the lower-level process model of the harvesting operation. Bottom-right: Proposed mapping from AAS interaction elements to BPMN 2.0 elements.
In this thesis, a novel approach for process-driven modeling and implementation of AAS-based Digital Twins shall be created. The system behavior of AAS-based Digital Twins (Operation, Events, etc.) shall be reflected by Colored Petri Nets, which allows to model and execute the Digital Twin based on one process model and process engine at the same time.
The architecture shall comprise the generic behavior-modeling of AAS-based Digital Twins using Colored Petri Nets with a suitable representation in other modeling languages such as BPMN2.0. The architecture shall allow to model and execute processes in an orchestrated (centralized) and choreographed (decentralized) manner and shall be evaluated in the Forestry 4.0 domain.
The concrete work procedure is given by the following:
- Familiarization with Industry 4.0, AAS, and Process Modeling Languages (BPMN 2.0, Petri Nets, etc.)
- Literature research of IoT process modelling, I4.0 Language, and AAS
- Process modeling architecture for AAS-based Digital Twins using Colored Petri Nets
- Accessing AAS-elements through AAS Registry and Repository
- Creating hierachical process models based on local functionalities and AAS-elements such as Operations, Events and Properties
- Modeling of orchestrated and choreographed processes
- Nice-to-have: Importing process models from other process modeling languages such as BPMN2.0
- Digital Twin implementation based on process model
- Extend already existing Implementation Basis of Colored Petri Nets (C++)
- Implement and deploy Digital Twins based on Colored Petri Nets
- Validation based on a Forestry 4.0 scenario
- Written elaboration and presentation
Supervisor: Bektas
