A new measurement method of wheel speed sensor without motor-driven gear based on electromagnet structure

Abstract Wheel speed sensor testing is one of the critical components of automotive safety evaluation. However, traditional motor-driven gear testing methods suffer from poor repeatability, inefficient work, and complex testing conditions. This paper proposes a novel testing method for wheel speed sensors, which employs a simulated gear device based on an electromagnet structure to eliminate the need for motor-driven gears. The method offers advantages such as low manufacturing cost, simple construction, feasibility for batch testing, and reduced air-gap influence. A physical model of the device was established and analyzed using the finite element method (FEM) to investigate variations in magnetic flux density under different geometric configurations. Based on the results of both FEM analysis and theoretical calculations, the simulated gear device can generate a rotating magnetic field similar to that produced during motor-driven gear rotation. The performance of the simulated gear device based on electromagnet structure was tested with multiple types of wheel speed sensors. The experiment result shows that the output levels are within the standard range of +20% to −16% and the duty cycle is within 30%–70% for current-type sensors. For voltage-type sensors, the high and low output levels remained within the standard ranges of 4.5–2.5 V and 0–0.5 V, respectively. Under conditions with lower cost and greater convenience, the test results are comparable to those obtained from a conventional motor drive test bench. The system operates normally under temperature environment tests conducted at 26 °C, −40 °C, and 150 °C. Combined with the results from small-scale batch testing, experiments demonstrate that the simulated gear device has good feasibility and reliability in testing of wheel speed sensors.