ROAD NOISE REDUCTION DEVICE, ROAD NOISE REDUCTION METHOD AND ROAD NOISE REDUCTION PROGRAM

To be able to reduce road noise transmitted to a cabin by referring to vibration of a tire itself.SOLUTION: There is provided a road noise reduction device installed in a vehicle body having a cabin and tires to reduce road noise generated by rotational contact of the tire with a road surface, which includes: a first microphone installed in a valve that injects air into a tire; a frequency conversion unit that converts a cavity resonance sound collected by the first microphone into a digital signal and converts the digital signal into a region of frequency in a frequency domain; a control signal generator that generates a control signal based on the signal converted into a region of frequency by the frequency conversion unit; a speaker that is installed in the vehicle cabin and outputs a countervailing sound that cancels the road noise based on the control signal; and a second microphone that is installed in the vehicle cabin and acquires the residual noise caused by interference between the countervailing sound and the road noise as an error signal. The control signal generator successively updates an adaptive filter so that the error signal is minimized.SELECTED DRAWING: Figure 1 【課題】タイヤ自体の振動を参照して車室に伝わるロードノイズを低減することができる。【解決手段】車室及びタイヤを有する車体に設けられ、タイヤが路面と回転接触することで発生するロードノイズを低減するロードノイズ低減装置である。タイヤに空気を注入するバルブに設けられた第１マイクロホンと、第１マイクロホンで収音された空洞共鳴音をデジタル信号にし、当該デジタル信号を周波数領域の周波数の領域に変換する周波数変換部と、前記周波数変換部で周波数の領域に変換された信号に基づいて制御信号を生成する制御信号生成部と、車室に設けられており、制御信号に基づいてロードノイズを相殺する相殺音を出力するスピーカと、車室に設けられており、相殺音とロードノイズとの干渉による残留騒音を誤差信号として取得する第２マイクロホンと、を備える。制御信号生成部は、誤差信号が最小になるように適応フィルタを逐次的に更新する。【選択図】図１