Digital thread-based modeling of digital twin framework for the aircraft assembly system

Digital twins are proposed to manage the industrial production sites by mapping physical space entities to virtual spaces. Existing digital twin modeling methods are mainly realized through deploying several modules, including a physical module, a virtual module, a service module, a data module, and a connection module. However, the assembly environment of the aircraft assembly process is complex and challenging to manage. These methods do not provide the data flow and the intrinsic interaction between modules. As a consequence, a digital threadbased modeling digital twin (DTDT) framework with five modules is established in this paper, which takes advantage of both the digital twin and digital thread. Benefited by better data management, the DTDT framework would be conducive to the controllability and traceability of the manufacturing process and product quality. The key characteristics of products, process parameters, and equipment operation conditions, are stored in the database module. And then, the digital thread module will link the entity module and virtual module together by building the directed graph, in which interfaces are provided to the system services module for the process monitoring and processing quality prediction. Finally, the implementation of the DTDT framework is shown through a case of the drilling and riveting process in aircraft assembly. The comparative analysis confirms that this model can improve the efficiency of the aircraft assembly process.