TU Kaiserslautern-Landau

Wireless Factory 4.0 with 5G

Massive Savings Potential, High Data Rates and Low Latency with 5G

5G Kaiserslautern

The 5G mobile communications standard is here and can now be used. However, small and medium-sized enterprises in particular are still unsure as to whether they should invest in a private 5G network. The investment seems too large and the return too uncertain.

The 5G Kaiserslautern project, funded by the Federal Ministry for Digital and Transport (Funding Code: VB5GFKAISE), shows which new applications can be implemented with 5G and how existing processes can be made more efficient.

Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau (RPTU)

The Rhineland-Palatinate Technical University Kaiserslautern-Landau (RPTU) is the only university in Rhineland-Palatinate with a technical and scientific orientation.

Harnessing the Strengths of 5G

At the Rhineland-Palatinate Technical University Kaiserslautern-Landau, 5G use cases are being researched in private 5G campus networks. The common goal of the research is to test the latest mobile communications standard in applications from various fields.

Each of the subprojects seeks to harness the three major strengths of 5G – a high number of network subscribers (mMTC), high data rates and volumes (eMBB), and reliable ultra- low latency (uRLLC) – for specific areas.

The CNC Mill as a Reference Case for Ultra-Low Latency

The extent to which latency can be reduced with 5G is demonstrated using a CNC milling machine in a workshop of the Institute for Manufacturing Technology and Production Systems (FBK). With 5G, the system manages without the usual on-site integrated control system, which has been relocated to the edge cloud. Instead, a standard tablet or smartphone is used as the control panel or human-machine interface (HMI).

The milling machine is a system with high precision, high torques and necessarily low latencies in machine communication. A latency of a few milliseconds must not be exceeded in regular operation. A milling machine can therefore be used to achieve a convincing reference case for low latencies.

"If we can achieve ultra-low latencies with high reliability for the milling machine, then almost anything else is possible," explains Jan Mertes from the Institute of Manufacturing Technology and Production Systems, who is leading the machine control use case. The overall project is led by Professor Hans Schotten from the Institute for Wireless Communication and Navigation. CNC milling machines typically have closed-loop control.

This means that there is no compensating input from human operators and the router operates automatically and independently, controlling the motion. The setpoint specified by the operator determines how motors, spindles and other machine parts move. Integrated encoders provide feedback on the actual position of the cutter, for example; controllers regulate the feedback loop around the setpoint position and actual position in under one millisecond. When the setpoint is reached, the operation must be stopped in real time.

The Digital Twin

Another research objective being pursued with the milling machine in the 5G network is to test the operational organization with a digital twin. This is the digital mirror image of the plant and all its processes. Via 5G, all values from the control system are transmitted to the digital twin. The digital twin is to be viewable in the plant network on smartphones, 5G-enabled tablets and 5G-enabled laptops. It monitors the machine in real time, enables diagnostics and in turn forms the basis of the control system.

Wireless communication in industrial automation is possible in real time with 5G.

Control units in industrial systems take up a lot of space.

Factory 4.0

The 5G standard can only be implemented with the right hardware.

One tablet to control all systems – this is the future of industrial production.

Jan Mertes is a doctoral student in the „5G Kaiserslautern“ project.

Flexible Reconfigurable Production

The 5G network eliminates the need for data cables. All that is needed to operate the machines is electricity and the infrastructure of the hall. At the RPTU, a fiber optic cable is connected to the machine hall, with which the 5G radio heads in the hall are connected to the core, thus establishing the 5G network. A central server is directly connected to the 5G network. The computing units, which are usually located on each individual machine, are outsourced to this edge cloud. Machines thus become mobile production modules.

Several modularly movable systems can be set up in such a way that production takes place in a minimum of space, saving time. An additive manufacturing system such as a 3D printer, for example, can be placed directly next to a CNC milling machine so that the finished printed parts can be immediately reworked. Afterwards, an AMR (autonomous mobile robot) or an employee can continue the process. The boundaries between production steps become more permeable.

Savings with 5G

In this machine control use case, almost 50 % of the cable infrastructure within the factory hall can be saved with 5G. A system without HMI also takes up less space. More systems can be accommodated in a factory hall or smaller halls can be built.

This saves resources. Since a 5G-enabled mobile device can act as an HMI for many machines, the device requirements for mobile devices are also reduced. "Naturally, the more systems there are, the greater the savings," explains Jan Mertes. "That's why a 5G project should be seen as a complete infrastructure project, as this can form the basis for a large number of simultaneous use cases."

Factory 4.0 with 5G

Small and medium-sized industrial companies in Germany are still hesitant about setting up their own 5G networks. However, Jan Mertes is convinced: "Once 5G is adopted, an increasing number of use cases will be developed." With 5G-based automation, it would be possible to organize the entire production from one control station. There would then only be stand-ins on-site to inspect a digital twin or a plant as needed.

Hurdles in the Implementation

The biggest hurdle for implementing the 5G project on the CNC mill was the availability of current, standard-compliant 5G hardware. Only with chips that technologically implement the 3GPP specifications for 5G Release 16 (R16) can uRLLC be achieved. Work on R16 has been completed since 2020. However, R16 chips could not be reliably procured during the Corona pandemic.

Zukunftsszenarien

Some of what is already possible and being tested with 5G may seem like something out of a science fiction novel.

Low latency is of high importance in CNC milling.

The mobile 5G network is set up from the car; the drone locates the weeds, and the robot selectively destroys them.

The fleet of AGVs performs a wide variety of logistics tasks on campus on demand.

Workers control systems via EEG. Important for this are eMBB and uRLLC.

5G in Every Respect?

The three strengths of 5G cannot yet be realized to the same extent in all use cases at present. For CNC milling, the transmission speed is enormous, while the data transmission rate is low. "For our use case, the data transmission rate is irrelevant," explains Jan Mertes, "because we only need to transmit a few kilobits to a few megabits."

With extremely low latencies, the data rate automatically suffers. If you need a high data rate with extremely low latency, only a few subscribers can use the network. "You ultimately have to decide where you really need excellence," Jan Mertes concludes. The other 5G subprojects of the RPTU confirm this.

Precision Farming with 5G

The agricultural use case requires 5G as a key technology for a high data rate and low latencies. Here, the 5G network is set up remotely from a transporter at the edge of the field. A drone flies autonomously over the field.

During the flight, large amounts of image data are transmitted, which is used in an edge cloud server to detect the weeds and calculate their position with the help of machine learning. Field robots then target the weeds and spray them with herbicides. Thus, with the help of modern technology, area-wide methods for sowing, fertilizing, by-product elimination or irrigation are being replaced by resource- and environmentally- friendly precision farming methods.

Intralogistics with AGVs

The use case with autonomous guided vehicles (AGVs) on the university campus also relies on the high data rates and low latencies that are possible with 5G. The existing fleet of AGVs at the university should be able to take over a wide variety of logistics tasks on the university campus on demand: from transporting books between two libraries, to delivering cafeteria food, to transporting materials for the workshops.

Since fully autonomous driving in a real environment is not yet possible, there is a control center from which an employee can intervene if a situation arises that the AGV cannot yet handle. To do this, the camera images must be transmitted in real time.

Augmented Worker

This case uses a brain-computer interface, with the help of which workers control equipment via EEG. On a semi-transparent display in front of the machine, workers see information on the status of a robot arm, sensor evaluations or other details about the workpiece in question.

The overlays and animations are calculated centrally on an edge cloud and monitored via a control station. On-site, only the visualization technology and the system for capturing the worker are needed. This use case is made possible by eMBB and uRLLC.