Health Indicators to Estimate Health of Magnetic Wheel Encoder



Published Nov 24, 2021
Jasmeet Singh Ladoiye Douglas Spry Milad Jalali


Performance of several vehicle safety features, such as anti-lock brake system (ABS), traction control system (TCS) and electronic stability control (ESC) rely on the quality of the wheel speed signal. One potential failure mode for the wheel speed encoders is gradual deposition of foreign paramagnetic debris on the surface of the magnetic encoder. This results in reduced strength of the magnetic field and impacts the quality of the wheel speed signal. Noisy wheel speed signals may lead to false activations or poor performance of ABS, leading to poor drivability, longer brake distance, etc. Therefore, it can negatively impact several safety critical features and the customer’s experience.

Data collected from several faulty encoders with various levels of faults were used to develop the prognostics methodology proposed here to evaluate a magnetic wheel encoder’s health. This method leverages time domain and frequency domain-based health indicators to monitor the deterioration in wheel encoder. Time domain-based health indicators include VDA (Verband der Automobilindustrie) signals that are generated by advanced wheel speed sensors, and an enveloping filter of the wheel speed signal’s noise. The frequency domain-based health indicator include root mean square amplitude of average order spectrum of wheel speed noise. The performance of individual health indicators as well as a combination of them are compared to assess the separation between healthy and degraded encoders. Results indicate that the degradation process due to magnetic debris accumulation can be monitored using the proposed method.

How to Cite

Ladoiye, J. S., Spry, D., & Jalali, M. (2021). Health Indicators to Estimate Health of Magnetic Wheel Encoder. Annual Conference of the PHM Society, 13(1).
Abstract 41 | PDF Downloads 22



Wheel Encoder Prognostics, Wheel Encoder Degradation

Technical Papers