Saying Goodbye to Communication Problems

The solution has come in the form of the VDA 5050 standard, an open source interface project initiated by the VDMA Materials Handling and Intralogistics Association and the German Association of the Automotive Industry, which is being implemented with various partners. With this communication interface, users can manage a fleet of heterogeneous mobile robots from different manufacturers via a single control system. Fraunhofer IML researchers have been involved in developing the interface for some time. The Dortmund-based research institute has put two in-house developments through practical testing this year: A pallet AGV with the innovative STUART chassis design, and the open source software libVDA5050++. STUART solves the issue of static over-determination seen in conventional four-wheel chassis without any need for expensive, high-maintenance springs, dampers or actuators. Thanks to its simple design, the STUART chassis can be scaled for any size and load capacity and is suitable for almost any application. It has one support wheel at the front one at the rear, as well as two drive wheels positioned at the center of the longitudinal sides, which form a central differential drive axis. All the wheels are connected by simple levers and joints, forming two linked support triangles. As a result, all four wheels maintain contact with the ground at all times, even when the ground is very uneven. This structure ensures the chassis is stable and prevents it from wobbling, which typically happens when machines like this start up and brake. This means that in many cases, there is no need to refurbish the flooring, a step that is often required prior to utilizing AGVs, in order to create floors that are “AGV compliant” (meaning flat and free of holes). As it is used in combination with a new kind of load transfer station for pallets, this AGV does not even need an active lifting mechanism for picking pallets up or putting them into storage. The load transfer station consists of two supports fitted with roller tracks. At the front, 50 cm of the roller tracks are tilted slightly downward, so the pallet is pushed onto the robot as it drives into the station. Then, as the AGV moves forward, the cargo pallet is lifted off the vehicle and transferred to the station. Depending on the type of station, the AVG can drive on through or reverse back out after it has delivered the load. To pick up a cargo pallet, the AVG drives into the station the other way around and collects the load using a simple loading mechanism. Fraunhofer IML has also developed an open source implementation of the VDA 5050 standard, libVDA5050++. This has been designed to be middleware-neutral and can be adapted to the individual needs of manufacturers and AGV users with little difficulty. libVDA5050++ encapsulates the entire control logic of the VDA 5050 standard so that it can easily be connected to an existing vehicle control system via a lean interface. In addition, libVDA5050++ reduces inconsistencies in implementation, meaning that it can act as a standard in the future.