Prognostics Model to Predict Brake Rotor Thickness Variation

Abstract

Brake rotor thickness variation causes brake torque variation which can lead to brake judder and pulsation, steering wheel oscillations and chassis vibration. In this paper, we have proposed a prognostics methodology to predict the degradation level of brake rotor due to disc thickness variation. Leveraging the time and frequency domain analysis, this model creates health indicators to assess the health of the rotor and predict the rotor thickness variations of 36 micrometers or more. These health indicators that are calculated during braking events include: (i) envelope or variance of the brake master cylinder pressure (MCP); (ii) envelope or variance of the longitudinal acceleration (AX); (iii) the root mean square amplitude of the average order spectrum of the MCP at order one; and (iv) the root mean square amplitude of the average order spectrum of the AX at order one. This paper demonstrates that the above health indicators are significantly larger for a degraded brake rotor due to thickness variation compared to a healthy rotor.