With 5g in the precipice: HBK measurement technology in the Formula 1 of winter sports

The measurement runs

In total 21 measurement runs were carried out in the ice channel at Königssee with the Bavarian bob team members Karl Angerer, Christoph Gaisreiter and Katrin Dostthaler. In total, a data volume of 43MB per measurement run was recorded, calculated on a signal width of 32 bit, a measurement frequency of 2,400 Hz over 48 individual channels and a recording duration of 100 seconds.

The measurement data generated was stored in MGCplus on a compact flashmemory card and then read and processed on a notebook with the catman® software. The data acquisition system was positioned between the pilot and the brakeman when measurement runs were implemented in the twoperson bob.

Particular attention was paid to the installation to ensure that there was no danger of injury to the bob team. The MGCplus was grounded via the bob frame and skids.

Measurement results

As specific optimization of skid geometry is only possible when load, location, time and position of the bob are known, all measurement results generated must be linked with the geometric and construction properties of the ice channel.

This was implemented by assigning the measurement results using an event map developed for the bob track. Figure 5 (see PDF file) shows a schematic diagram of the bob track in combination with the recorded axle load of a two-person bob.

The various events in the ice channel can be clearly recognized as sensor signals in the diagram. Because of the centripetal forces acting on the bob, the axle deflection and the sensor signal acquired increases quadratically with increasing speed and linearly with decreasing track radius. 

At the last steep curve, the echo wall, the force acting on the pilot and team rises to five times their body weight. The bob is subject to the maximum force at this point.

Assigning the loads

The position of the bob was precisely determined using the signal for the precise assignment of loads to the corresponding location in the ice channel. This can be implemented by integrating the speed over time.

The speed can be determined by comparing the axle signals: The deflections of the front axle were repeated after a slight time delay at the rear axle.

The average speed could be determined because the axle distance of the bob was known.

Bob sport and measurement technology in the future

Greater competitive pressure and ever faster equipment requires systematic procedures in all further developments in this winter sport. Measurement technology holds a key position here as it can provide statements about arising loads and it can be used as the basis for verification of simulations.

Based on the measurement results recorded at the ice channel in Berchtesgaden, an FEM model was created at the Zentralinstitut für Medizintechnik of the TU München which permits the simulation of the measured processes.

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