IIoDT: Industrial Internet of Digital Twins for Hierarchical Asset Management in Manufacturing

The Internet of Things (IoT) and digital twins (DT) are emerging technologies in the industry 4.0 landscape. Both technologies offer the capabilities of collecting and analyzing large quantities of data and utilizing this data for intelligent decision-making. These technologies together form the Industrial Internet of Digital Twins (IIoDT). Currently most works on DTs in literature focus on a single level of the manufacturing hierarchy without considering the interactions among levels. It is important to understand how these different scales of DTs can interact together in order to create a scalable system. The various assets in a manufacturing environment exist in a hierarchy with information flowing up from the lowest level to the highest. Additionally, information flows from various levels to a central database and data processing center. DTs connected in an IoT network can provide various services for asset management in manufacturing such as condition monitoring, health assessment, simulation, forecasting, and visualization. It is important to understand the various capabilities and interactions between the various DTs. This work examined DTs at multiple levels along the manufacturing hierarchy, what value they can provide, examples in the literature of DTs at each level, and how they can interact with other DTs along the hierarchy. This IIoDT system can be used to analyze both vertically along the hierarchy and horizontally across assets of the same level. This framework can help bridge link the various levels of DTs that exist to better integrate them in a manufacturing system.