Erfaringsudveksling i Vandmiljøteknikken EVA
12
Digital Twins
Af: Hugo Daniel Macedo Ph.D., Research Assistant Aarhus Universitet, Digital Twin center
A digital twin is a concept, an abstract idea, which is associated with the smartest technological solutions that our digital era advances can offer. The concept is about 20 years old and its popularization started later as hinted by the 2015 timestamp in the creation date for its Wikipedia entry.
In the last couple of years, digital twins have been deemed as overhyped or nothing beyond a buzzword, but there is a reason why the concept is here to stay, and it has to do with how intuitive the idea is. A digital twin can be understood as digital model counterpart of (a) physical asset(s), and the model is so precise that one can use the digital twin to operate/predict/optimize the physical counterpart, as it becomes indistinguishable from the physical object itself. In the domain of water operations, a primal version of the digital twin is second nature, known by a different name, as water operations management and control is now fully digital and controlled by advanced SCADA systems, but it is still difficult to find a uniform definition of what is as pointed by (Pedersen, 2021). In this text and the other articles in this edition, we hope that the readers can grasp the variety of perspectives associated with a DT, and given the increasing amount of publications/hype around the concept, it is understandable how easy it is to not see the forest for the tree. Therefore, we lay down the basics of the idea by connecting it with the domain of cyber-physical systems, which adequately fits the standard concepts associated with the systems deployed in the water domain, and we characterize such a system as operating in a digital twin setting wherever the physical asset and the digital model satisfy three mathematically ground relations. But first, a glimpse at what a cyber-physical system is...
The Elements of Cyber-Physical Systems
A cyber-physical system is a computer system connected to a physical system via sensors and actuators. In this class of systems, computation reacts to/produces changes in the physical sub-systems to affect/influence its behaviour over time. It is usual to consider the following elements: • a controller – device hosting the computation process, • a plant – the physical system, • sensors – devices providing measurements, • actuators – devices affecting the plant, • environment – the common ground where all the above elements lie and interact with.
