The FIWARE middleware is KITT4SME's IoT communication, data exchange and interoperability backbone.
FIWARE is an open-source platform to build IoT applications and comprises a curated set of components implementing the NGSI interoperability specifications.
KITT4SME assembles a selection of FIWARE components into a middleware to support the Sense and Intervene phases of the KITT4SME workflow. During the Sense phase, this middleware allows KITT4SME application services to acquire data from the shop floor through a diverse range of IoT devices and cyber-physical systems such as wearable devices, environmental sensors, cameras and robots. The same middleware makes information flow in the other direction too, i.e. from the platform to the shop floor, as AI components issue commands to control devices or suggest corrective actions during the Intervene phase of the workflow.
The middleware also provides a foundation for interoperability, tracing of data transactions and multi-tenancy. Instead of interfacing directly with the shop floor IoT environment in an ad-hoc fashion, KITT4SME application services interact with the shop floor through the FIWARE middleware, using standard, interoperable APIs and data models defined by the NGSI specifications. The middleware tags each data transfer with the platform tenant who owns the data as well as a transaction identifier. The KITT4SME security infrastructure then uses this information to enforce security and trace data transactions.
The FIWARE middleware is a set of platform infrastructure services. Together, these services constitute the platform's IoT backbone through which a digital representation of the shop floor (the IoT "context" in FIWARE parlance) is created, queried and possibly manipulated to control physical devices in the factory. The FIWARE middleware makes the IoT context available as a distributed graph on which platform application services can operate by means of REST APIs as specified by the NGSI standards.
The middleware includes several FIWARE services as well as backend databases:
- OrionLD. A FIWARE Context Broker implementing both the NGSI v2 and LD specifications. It maintains IoT context data and publishes context changes. Typically, platform application services rely on OrionLD to get notified of changes in the shop floor IoT environment during the Sense phase of the KITT4SME workflow. Application services may interact with OrionLD in the Intervene phase too—e.g. to send high-level commands to shop floor devices.
- QuantumLeap. A FIWARE IoT context management service. It tracks changes to the IoT context to build a history of context changes which then makes available to query over space and time through a REST API. KITT4SME leverages QuantumLeap's ability to track time varying measurements in the IoT context to provide platform application services with time series of shop floor measurements.
- Agents. A set of FIWARE services to interface with the shop floor IoT environment. Together, these services act as a data translation layer at the platform's boundary, mapping external data to instances of NGSI entities in accordance with the KITT4SME data models. They also translate high-level commands issued by application services into low-level instructions which IoT devices can understand. This layer comprises several software components that can interface with external systems using widely implemented standards such as OPC UA and ROS.
- Databases. A set of databases (MongoDB, Postgres, etc.) to provide the persistence backend for the above services. Note that these databases also provide a persistence backend to several platform application services.
The FIWARE middleware services rely on the underlying KITT4SME mesh infrastructure for security, scalability and automated deployment. As infrastructure services, their role is to support the operation of application services, so unlike application services they are not available in the RAMP marketplace. Below is a visual to summarise the role of the FIWARE middleware in the KITT4SME architecture.
The DoA committed to a FIWARE-based IoT platform and interoperable solution to facilitate the integration of application services and shop floor software. The FIWARE middleware has been developed to fulfill exactly these requirements.
Except for QuantumLeap, no other middleware component has required any modification to their respective code bases. However, a significant amount of effort has gone into the plumbing needed to deploy and run the middleware components on the mesh infrastructure. This has entailed the development of Kubernetes and Istio manifests, Argo CD projects and applications, and the fine-tuning of the middleware components themselves. An early version of the middleware was open-sourced in Q2 2021 as part of the initial platform prototype developed to validate the KITT4SME architecture and is still available at: https://github.com/c0c0n3/kitt4sme. The middleware has since evolved into the current open-source version at: https://github.com/c0c0n3/kitt4sme.live. The work has been carried out in WP 2 as part of the FIWARE middleware, persistence and deployment tasks.
Although the FIWARE middleware provides no direct business value to KITT4SME end-users, it is a key component of the platform infrastructure that enables the operation of application services delivering actual business value. Unlike proprietary solutions, FIWARE is open-source and based on time-tested IoT standards which dramatically reduce the effort required to integrate application services and shop floor software into an IoT continuum.