Exterior view of the subsystem
Principle of operation
The system was designed based on inductive fast-response proximity sensors. Total number of sensors – 32 (16 sensors per each side). The sensors are fixed on the rail at the distance of 30 cm from each other. Each sensor is an inductive four-coil bridge with a ferrite core and power supply from excitation winding (frequency of 100 kHz). In the initial condition, the AC output signal is equal to zero. A metal object approaching to the sensor results in changes in inductance of the respective pair of coils, which leads to bridge unbalance and generates an output AC signal, the value of which depends on the distance between the sensor and the wheel flange.