Detection of wheel faults with smart algorithms
Wheel faults lead to high loads on the railway infrastructure and generate noise. SCS has developed algorithms for recognising wheel faults. This means that affected vehicles can be repaired accordingly.
-
Initial situation: Wheel fault
Wheel faults (e.g. flat spots, chipping) lead to high stress on the infrastructure and generate noise. Various data must be linked and analysed to record different wheel defects.
-
SCS solution
SCS has tested and implemented various algorithms for recognising wheel faults. The procedures are based on the signals supplied by the RLC.
-
Benefit SBB
The presence of wheel faults is recognised. An estimate of the severity of the wheel defect is made for certain wheel defects. Affected vehicles can be reported to the railway undertaking so that it can repair the vehicles.
RLC systems (wheel load checkpoints) measure the weight of passing vehicles as part of the train control equipment (ZKE). The signal curves are influenced by wheel faults. The signal curves can therefore not only be used to determine weight, but also indicate whether wheel faults are present.
In the first approach for determining a wheel error, an easily determined parameter (dynamic coefficient) is calculated from the signal curve of each wheel. If the dynamic coefficient is small, there is no wheel error and if the dynamic coefficient is large, there is a pronounced wheel error.
In the second approach, an algorithm developed by SCS detects flat spots and estimates their length. It utilises the fact that a typical signal curve results from a flat spot that occurs exactly above a sensor. The algorithm searches for this typical signal curve on the measurements. If one is found, it is analysed in more detail by the algorithm in order to estimate the length of the flat spot. To estimate the length, characteristic points must be determined on the signal curve.

In the third approach, the “unwinding” of the wheel is determined, i.e. the outside of the wheel and its condition are shown on a graph. This provides a condition of the wheel over the entire circumference and the individual defects on the tread are visualised. As the sensors on the RLC system do not cover the entire circumference of the wheel, additional sensors are used for processing. The algorithms developed by SCS process the measured data from the individual sensors and then combine them to produce the processing.

The three approaches allow existing wheel defects to be detected and analysed in more detail. Based on the analysis, a recommendation can then be issued for the refurbishment of vehicles with wheel defects.
Cover picture: Heitersberg [CC-BY-SA-4.0] via Wikimedia Commons (cropped)
