Marc Westphal, Bayer
A digital twin is a comprehensive digital representation of an identifiable asset. It is an entity that not only represents the current state of the asset but can also store historical data, for example data covering the entire lifecycle of the asset. It may also reflect links to digital twins of other assets.
Even though the term "digital twin" was first defined some 20 years ago and became a hot business topic five years ago, we are only now able to begin reaping the potential of this technology. Open platforms and industry standards such as the Asset Administration Shell, or AAS, support these efforts. They are actually prerequisites for implementing digital twins.
Unfortunately, the definition of an asset administration shell is technically complex, scaring off some companies and getting in the way of industrial digitalization.
There are two approaches that can help simplify this.
The theoretical approach defines the digital twin on the basis of specific maturity levels during the product lifecycle. It differentiates between how an asset was designed ("as engineered"), how it was manufactured ("as built"), and finally, how it is being maintained ("as maintained"). At each maturity level, new or additional information becomes available that is digitally linked to the asset. If we apply all this to safety valves made by LESER, it would mean that for every safety valve delivered to us as the customer, a digital twin would be available at the lowest maturity level, the "as built” level, which comprises manufacturing bill of materials information (MBOM) as well as information about spare and wear parts. When LESER provides us with maintenance information, the maturity level will advance to "as maintained".
What is actually of greater interest to the industry as a more pragmatic approach would be a version of the digital twin based on its possible implementation, i.e. as an Asset Twin, Product Twin or Line Twin.
This approach places greater emphasis on the application aspect and the interlinking (or collaboration) of the digital twin with various "partners". An Asset Twin, also referred to as a Master Data or Information Twin, reflects the initial and most basic composition of the asset. It is a purely digital representation of the entity as manufactured and supplied. This implementation, along with other information collected from master data, documents, CAD documents and bills of material, enables new application scenarios. Examples include the digital nameplate or ID link.
The next development step, called Product Twin, opens up opportunities for predictive maintenance when combined with additional IoT data (from sensors and controllers). The highest level, or Line Twin, is interlinked with all digital twins of a process line, enabling the simulation of entire processes. The implementation of a digital twin we are currently addressing is the Asset Twin. Together with LESER, we have collected and reconciled all information needed for a digital representation of safety valve master data. In this process we apply industry standards such as ECLASS and VDI2770. This work has prepared the basis for using an information platform to generate and use future Digital Product Passports (DPP).