
Digitization of Engineering documents applying Model-Document Coupling

Idea and purpose
In the context of technical innovations, changes to processes, products, and production occur regularly. This results in changes for corresponding models and documents which partly contain overlapping information and can lead to inconsistencies. In particular, changes to documents mean that these documents are no longer or only partially can no longer or only partially be interpreted by computer machines. As a consequence, conventional methods of inconsistency management are no longer applicable. A Model-Document Coupling approach aims at systematically coupling (modified) documents with their original models and thus technologically supporting reverse engineering in case of changes.

Requirements
In order to link documents with models, the following requirements must be met: (1) Documents and potential changes must be described using a modeling language, (2) a bidirectional transformation between document and models must be designed, and (3) a matching methodology between two information sources (model and document) must be defined.

Participants
A Model-Document Coupling always makes sense between two arbitrary actors if these actors work on different information sources (e.g. SysML requirement model in one tool and exported requirement specification in the form of a PDF document) and at the same time conventional methods of inconsistency management are not applicable.

Temporal and spatial structure
A Model-Document Coupling can take place throughout the entire life cycle of a mechatronic system. In early life phases, documents can be generated automatically out of models, thus preventing inconsistencies. In late phases, Model-Document coupling can be used to reconstruct “readable” and use case specific models for computers from hardly interpretable documents.

Procedure
The following left figure shows the basic structure for the design of a Model-Document Coupling Framework, which consists of two transformation machines. The following figure on the right shows the general structure during the reverse engineering of documents that enables the “reconstruction” of models from documents.


Use case
The CRC 768 demonstrates the applicability and usefulness of a Model-Document Coupling approach in the following application cases (link to publication):
- Generation of functional specifications documents from requirement models in SysML (IEEE ICIT 2017)
- Reconstruction of requirement models from modified functional specifications documents (IEEE ICPS 2019)
- Generation of modular IEC 61131-3 control software from SVG-based P&I diagrams in the process engineering domain (IEEE ISSE 2018)
- Reconstruction of ECAD-similiar models from handwritten annotated circuit diagrams, so-called redlinings (IEEE IECON 2018)