Active headrest of an electric vehicle combined with the FxLMS algorithm and the remote microphone technique

The active headrest can reduce the low frequency noise around ears based on the principle of active noise control. This paper presents a multi-channel adaptive feedforward active headrest combined with the remote microphone technique. It reduces tyre-road noise at the ears of an dummy head in an electric vehicle cabin by the FxLMS algorithm. In the practical application, it is inconvenient to directly install physical error microphones at the ears. Therefore, the remote microphone technique is adopted by properly selecting the positions of the monitoring microphones to avoid the arrangement of microphones at the ears. Besides, a modified method to estimate the disturbance signals at the ears is proposed to improve estimation accuracy. Experiments have been conducted on the front right seat in an electric vehicle. The results show that the active headrest effectively reduces the broadband random noise around 5 dB below 500 Hz at the ears during the driving of the electric vehicle.