Overview of VDA 5050 – the VDA communication interface for AGVs
VDA 5050 is the definition of a communication interface for automated guided vehicles (AGVs). The current version (as of August 2021) is 1.1, which was released in June 2020 and was defined in a collaboration between the German Association of the Automotive Industry (VDA) and the German Engineering Federation (VDMA). The communication interface is used to exchange status and order data between automated guided vehicles (AGVs) and a central control system.
VDA 5050 is designed as a universal interface to
- easily integrate new vehicles into an existing control center
- simplify the integration of new AGVs into an existing AGV system
- enable the parallel operation of AGVs from different manufacturers in the same working environment
Originally, the communication interface was developed with the requirements of the automotive industry in mind. However, since these requirements are so diverse even in this industry sector, there is still plenty of scope for special cases, specific application scenarios and individual circumstances. As a result, the control center and AGV cannot always communicate with each other without problems, even though they both support VDA 5050. Despite standardization, it is still necessary to check which factors should be used for communication. Nevertheless, the VDA 5050 leads to a significant reduction in integration effort and complexity.
Communication channels using VDA 5050
The communication channels can usually include the following participants:
- ERP/warehouse management system
- Control center or control system
- Message broker (specifically: MQTT broker)
- Automated guided vehicle systems (AGVS) and fleet managers
The control center communicates with the warehouse management system and the ERP system, i.e. the business resource planning. Both parties to this communication are indispensable – unlike the fleet managers. The optional fleet managers are now integrated into numerous AGVs and take on tasks that can also be controlled by the control system. For example, the battery charge status can be communicated via both the control system and the fleet manager. This means that either the control system or the fleet manager instructs the corresponding AGV to drive to the charging station and recharge the battery. This responsibility must be clarified in advance. In this way, it is also necessary to define in other AGV functional areas which aspects of VDA 5050 should be specifically applied in communication.
Systemically, separate information complexes are facing each other with the central control system and the fleet managers. While the central control system knows the possible routes and the respective transport orders, the AGVs also form a kind of unit with the manufacturer-specific fleet managers. So a bridge needs to be built between the different information agglomerations. The message broker is designed to fulfill this requirement. This system is based on several queues called topics. With the help of this functionality, the message broker opens the closed sphere of manufacturer-specific fleet managers. As an intermediate layer, it subsequently makes it possible to connect additional hardware or even another system to the control system. In this way, both players can simultaneously send messages to a topic and also read them. For example, a fleet manager can send a message to a topic of the message broker while the control system is already retrieving this message from the message broker.
What is the MQTT protocol?
MQTT stands for Message Queuing Telemetry Transport. It is an open network protocol for machine-to-machine (M2M) communication. Telemetry data is transmitted in the form of messages – a principle that works even when there are long delays (latency times) or limited networks are involved. An MQTT broker is a server that can function as a state database, is particularly suitable for automation solutions and is widely used in the broad field of the Internet of Things (IoT). This is where a wide variety of devices come together that can communicate data accordingly – from sensors and actuators to smartphones/handhelds and systems integrated into vehicles.
Pull principle for VDA 5050
VDA 5050 is based on the pull principle. This means that the participating systems do not passively wait to be instructed to perform an action. Instead, each system must itself (and thus actively) establish a connection to the message broker and then be ready to forward, process or execute actions when a valid topic occurs. Systems that process according to the push principle must be converted accordingly. The pull principle is particularly effective with VDA 5050 because each communication participant, i.e. each system, decides for itself what type of information or message it wants to receive. This means that the individual systems are not burdened with data that is irrelevant to them and the corresponding processes.
Conclusion
The VDA 5050 is a standardized communication interface that automated guided vehicles use to exchange status and order data between automated guided vehicles and a central control system. Generally speaking, the interface makes it easy to integrate new vehicles into an intralogistics ecosystem, including AGVs from different manufacturers. This means that different AGVs and AGVs with different systems can be operated in parallel in the same working environment. The major advantage of this is that there is no longer any need to restrict yourself to a single brand or a single system. This does require some effort and possible adjustments in advance, but it then greatly reduces complexity at the operational level and offers companies an enormous increase in the possibilities for flexible automation and customization with regard to the AGVs and AGV systems used.
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