Understanding the concept of a Digital Twin
You have probably heard someone talking about Digital Twins in the last few years. You could even say that it has been a buzzword for some time. But since 2019-2020, it's become more than just a buzzword. Organizations and people have started to understand the benefits of having a Digital Twin. There has even been a large increase in organizations that want to start and implement a Digital Twin.
But what is a Digital Twin? I get that question a lot. And every time it is difficult to come up with an answer that others will understand. And even referring to the definition on Wikipedia will not make it easy to understand. There are a lot of different definitions you can find online in articles and blog posts. To explain what a Digital Twin is requires a definition to start with followed by a more in-depth explanation of the definition itself. I use the following definition:
You may have noticed that this definition contains several terms: digital replica, entities, and reality. It becomes clearer when explaining each of them in more depth.
Digital replica
A digital replica is a way of storing several entities and their relationships in a specific model. Such a model is stored in a location according to your requirements and needs. An example could be a database or service. Each product on the market that is available to create a Digital Twin has its own way of storing the information that describes the model. That means that the digital replica can describe a real-life situation using definitions and parameters. Think of a machine and whether it is turned on or off. The digital replica would describe the machine and its state. But a digital replica could also be about a collection of machines and their relationships. Think of a machine that is creating a product and the machine that is packing the product. The packing machine requires products to pack anything. That relationship is also described in a digital replica.
Entities
Entities can be different things. An entity can be anything from a physical living being such as people to a physical non-living thing such as processes, machines, buildings, equipment, rooms, and devices. When we talk about physical, it means being physically part of the reality from which you create a digital replica. Each of these entities has a specific purpose within the model. An entity is described by its characteristics that are relevant to the model and what you try to achieve in your solution. An entity could be a temperature sensor installed in a room. The characteristics are then the location of that sensor, the temperature the sensor is measuring, and the notifications it is raising when the temperature gets too low or too high. The location in this case is the room where the sensor is located. That characteristic is a relationship to another entity called the room. All these characteristics when developing Digital Twins are described by properties and metadata.
Relationships
An important part of a Digital Twin is the way entities are related to each other. These relationships are important as they define the context in which the entities are depending on each other and are a part of the reality on which the model is based. A relationship itself defines a set of data based on how the relationship is defined between the entities. An example is the relationship between the temperature sensor and the room where it is installed. This relationship defines what the temperature is within the room. Business rules can be used to take certain actions based on entities and their underlying relationships. An example would be switching off the lights within the room when there is no movement for a pre-defined time. In that situation, the lights, motion sensor, and room are each an entity with underlying relationships.
Realities
Each entity is part of a reality. Normally the reality would be a part of the physical world around us, like the example of the temperature sensor in a room. In that case, we have an actual device, room, and building. But imagine a world that represents a theoretical reality. This could be a virtual, generated reality that acts as the source for the digital replica. An example would be a digital world created in virtual reality or even another Digital Twin.
You have just learned about the concept of Digital Twins and its elements. This is important since it will help you to understand how Digital Twins can be applied to different scenarios. In the next section, we will explore the different parts of the environment around a Digital Twin to implement Digital Twin solutions.