Active control of road noise considering the vibro-acoustic transfer path of a passenger car

This paper presents an efficient approach to select the reference sensor position in active control of road noise by considering the vibro-acoustic transfer path of a passenger car. To ensure sufficient noise attenuation in active road noise control, the reference signals should be correlated with vehicle interior noise signals. To achieve this aim, the vibro-acoustic transfer path delivers promising options. An appropriate number of reference signals have generally been obtained by principal component analysis. Then reference sensor positions have been determined by evaluating a large number of candidate locations on a car from a coherence perspective. However, this task is time-consuming and inefficient in the actual vehicle development process. Furthermore, in practice, it is challenging to obtain a highly coherent reference signal for road noise with broadband noise characteristics without understanding the characteristics of the road noise transmitted to the interior of the vehicle. In this study, a structural transfer path analysis was conducted to derive the primary vibro-acoustic paths of structural road noise, and the optimum positions of the reference sensors were determined through the analysis of path contribution and vibro-acoustic transfer function. A practical active noise control system was implemented with the remote microphone technique based on a vehicle audio system to validate the noise attenuation performance. The experiments demonstrated an average attenuation of 3.4 dB at the driver and rear right-hand-side seat positions for up to 400 Hz frequencies. This approach is expected to increase the efficiency in developing active road noise control systems based on adaptive feedforward control systems.