Design and Test of Composite Relative Position Sensor for High-Speed Maglev Track Measurement System

A composite relative position sensor is studied in this paper. The sensor outputs square signal corresponding to the cogging cycle of long stator track, which is used as the spatial sampling pulse for high-speed maglev track measurement system, and also provides relative position, speed and direction information. The sensor uses only one group of detection coils to identify the cog and two photoelectric switches to identify the direction, thus effectively reducing the mass and size of the sensor. To make sure the sensor works normally when it vibrates vertically and passes through the track joint, the processing methods are given respectively. The factors that affect the dynamic response characteristics are analyzed and compared, it is considered that the discharge time constant of the demodulation has a great influence, and based on this, the detection speed limit of the sensor is calculated as 253km/h. The dynamic test is carried out by using the equivalent inductance method, and the results show that the sensor can respond normally and output the results correctly within the speed of 200km/h. In addition, it is demonstrated that the sensor can detect accurately within a detection distance of 22mm and a lateral deviation of ± 22mm through platform test.