Digital twins and Twins

A digital twin in general is a digital representation of a physical asset, such as a machine, vehicle, product, or of a virtual or logical thing, such as machine type, product type, a server, a fact sheet etc.

There are several ways to put the concept of a digital twin into practice.

The Digital Twin Registry provided by Bosch Semantic Stack accepts two types of digital twins, listed in the table below.

Type of digital twin Provides asset data via …​ Supported by Digital Twin Registry

Digital Twin (we prefer to simply call it Twin)



Asset Administration Shell




At Bosch Semantic Stack, we like to refer to our Digital Twins — the ones that hold aspects — just as Twins.

Such a Twin exists as an entry in the Digital Twin Registry.

One Twin groups the data produced by a physical asset (or provided by other systems about this asset) into coherent pieces of information: the aspects. That means, the Twin itself does not provide data about the asset. Instead, one or more aspects are associated with the Twin in the Digital Twin Registry, each of which provides the actual data.

For example:

  • The Twin of a spot welding machine could have aspects for measurements of the welding process, its maintenance status, and for its online status.

  • The Twin of a vehicle could have information about its movement, its environment, its engine, and its current configuration.

Twins in the Digital Twin Registry can be registered, deleted, and discovered, and aspects can be added to and removed from existing Twins.

When adding an aspect to a Twin in the Digital Twin Registry, the aspect’s endpoint for one of the supported aspect data transports (HTTP or MQTT) is added together with the unique identifier of the Aspect Model that describes the payload that is delivered by the endpoint.

semantic stack layers

Asset Administration Shells

Refer to the Asset Administration Shell (AAS) concept page.