Reliably transmitting more and more data

The radio-based control of automated guided vehicles (AGVs) is becoming increasingly demanding. In complex industrial environments, it must be possible to transmit more and more data reliably, which is not always possible with conventional technologies. Götting KG, a leading supplier of sensor technology for vehicle automation, has now been able to test a number of special applications with EchoRing technology, thus opening up new potential uses for AGV control.

A concrete example is the "Cooperative Transport of Goods", i.e. the transport of large and bulky loads with the help of several small vehicles which, due to their scalability, can be used more cost-effectively and flexibly than a single, large heavy goods vehicle. Here, the individual vehicles are not connected mechanically, but via a "virtual drawbar", but must be able to act as an integrated system.

"One of the challenges is to keep the relative positions of the vehicles to each other very precisely constant over longer distances, even during the transport process, so that no mechanical forces are transferred to the load being transported," explains Thomas Neugebauer, head of the development department at Götting KG. Via an EchoRing radio link, the required position and status data of the vehicles could now be exchanged cyclically and absolutely reliably among each other, so that Götting could prove the safety of the technology for position control of "virtual drawbars".

In addition to AGV control, EchoRing also proved itself at Götting KG in use with automated guided vehicles (AGVs), especially in the infrastructure-free communication of vehicles when approaching intersections, junctions or other decision points. Usually, FTFs or AGVs (Automated Guided Vehicles) receive their driving orders via WiFi or a campus network from a central control system, which also takes care of traffic regulation at critical points in order to avoid congestion or even collisions.

If the communication system is disrupted, vehicles usually come to a standstill, which can cause mutual blockades at intersections, for example. To avoid such disruptions or to relieve the central communication network, the vehicles can be equipped with the EchoRing system as a reliable redundant system. At neuralgic points, the AGVs then exchange information directly with each other and regulate the right of way autonomously. Current transport orders can thus be completed without downtime and operations can be maintained.

As part of a research project, Götting KG is also using EchoRing in combination with an LTE Sidelink transmission system. As an infrastructure-free data transmission system, Sidelink is part of the cellular networks in the 4G or 5G standard and is also intended to serve communication between vehicles in road traffic in the future. To investigate a software-based implementation, two Sidelink radio systems were mounted on two AGVs that travel predetermined routes with different environmental characteristics.

The position control is done via an EchoRing radio link. "Thanks to the special architecture of the EchoRing system, the data transmission works absolutely error-free even if there are obstacles in the radio path," says Götting development manager Thomas Neugebauer, summing up the results so far. Neugebauer adds: "Not only, but especially in difficult environmental conditions, EchoRing represents an advantageous and reliable solution for the navigation of driverless systems."