Measurement of Acoustic Sensitivity of Automotive Drum Brake to Multiple Faults

Multiple faults can occur over time in drum brakes, which are commonly used on the rear of heavy vehicles and two-wheelers, compromising passenger safety and ergonomics. Given the recent success of artificial intelligence in fault diagnosis, it can be applied effectively to automotive brakes during operation when combined with advanced measurement techniques. However, monitoring the brake health during operation is challenging due to the rotational motion of components and space constraints for sensors. Consequently, this study investigates the use of measured radiated noise from drum brakes (instead of vibrations) to detect faults. A test bench mimicking typical on-road braking dynamics has been developed to operate in a controlled environment with pre-determined fault levels. This setup measures acoustic signals during transient brake events. Acoustic responses from several experiments that imitate three common brake fault conditions are measured. The acoustic sensitivity to each fault is estimated (along with its physical interpretation) by using time and frequency domain features. Subsequently, unique signatures indicative of specific fault types have been identified. These results are promising as they could facilitate the development of a novel non-contact acoustics-based in-situ health monitoring system for brakes.