Tunnel boring machine: Preventing cable failures through wireless data transmission for rotating and moving components

Tunnel boring machines are among the largest and most complex mobile production systems in the world. They handle every stage of the process in the construction of road and railway tunnels – from the actual boring operation and the removal of excavated material to the installation of the tunnel walls. Modern machines can reach lengths of over 200 metres and diameters of up to 18 metres.

The rotating cutter head on the drill head plays a central role in this process. Sensors there record important operating data such as rotational speed, pressure, temperature and material values, which must be continuously transmitted to the control system to ensure safe and precise tunnel construction.

For a current tunnel project, the Chinese manufacturer CREG (China Railway Engineering Equipment Group) opted for wireless PROFINET communication using DATAEAGLE radio systems.

 

Data transmission from the rotating cutting wheel to the stationary control system poses significant technical challenges.

On the one hand, the components are constantly moving relative to one another, which means that conventional cable connections or slip rings are only of limited use. On the other hand, space within the drill head is extremely confined and the environment is highly conductive, which further complicates wireless communication.

At the same time, reliable transmission of sensor data is essential, as this information has a direct impact on the control and safe operation of the tunnel boring machine.

DATAEAGLE 4000 Series wireless modules, which were specifically developed for the transmission of Wireless PROFINET and PROFIsafe, were used to implement the wireless communication.

The slaves were installed directly on the rotating cutting wheel, whilst the corresponding masters are located in the stationary section of the rotary head. From there, the data is transmitted via cable to the central control system.

DATAEAGLE modules of types DE 4713 and DE 4715 were used for multi-point and point-to-point connections. Communication takes place via Bluetooth with frequency hopping, ensuring stable and interference-free data transmission even in a highly metallic environment.

In addition, the patented data pre-processing of the DATAEAGLE systems ensures that any potential radio interruptions do not cause bus errors and that high communication availability is maintained.

• DATAEAGLE 4000
• PROFINET

The DATAEAGLE radio links used have proven to be reliable even under the demanding conditions of a tunnel boring machine. Despite the confined installation space and rotating components, the sensor data was transmitted stably and without interference.

The successful integration of the Wireless PROFINET solution demonstrates that industrial wireless technology represents a powerful alternative to traditional cable connections, even in highly complex and safety-critical applications.

Yong Liu of Shanghai Hysea Industrial Communications Ltd summarises the results as follows:

“We conducted intensive testing of the DATAEAGLE’s PROFINET functionality in the TBM prior to its final deployment, with excellent results: the sensor data from the rotating machine parts was reliably captured even in this confined environment and transmitted just as reliably by PROFINET to the control system.”