基于时频感知加权的车辆路面冲击声品质评价

为表征与量化人对路面冲击声的主观感受,首先,对减速带工况冲击非平稳噪声信号进行声时感知时长定义,同时根据人耳听声可辨性将声时历程分为冲击段、峰值段及衰减段;进而,以小波变换提取冲击噪声中的主冲击与多重微冲击特征信息,组成冲击声品质评价的基础特征阵;然后,类比峰值因子法定义频域滤波因子,并基于序关系分析法确定时变感知加权系数,组建时频滤波网络对基础特征阵加权且建立冲击声品质时频感知评价指标;最后,基于实车过减速带冲击噪声测试数据计算声品质指标,并进行对比验证.研究结果表明：所提时频感知加权评价指标与主观评价的相关系数在车速20 km/h时为0.927,在车速30 km/h时为0.922;在考虑路面冲击声声时历程全程评价时,经典的声品质评价指标（特征频带时变响度）与主观评价的相关系数在车速20 km/h时为0.933,在车速30 km/h时为0.649;所提时频感知加权评价方法对于车速为20 km/h与30 km/h的情况具有较好的适用性.

Evaluation of Vehicle Road Impact Sound Quality Based on Time-Frequency Perception Weighting

In order to characterize and quantify a person’s subjective perception of road impact sound, firstly, the acoustic time perception duration of the impact non-stationary noise signal of the speed bump condition was defined, and the acoustic time history was divided into the impact section, the peak section and the attenuation section according to the discernibility of the human ear. The main impact and multiple micro-impact feature information of the impact noise were extracted by the wavelet transforms, and the feature information was used to form the basic feature matrix for impact sound quality evaluation. Then, the frequency domain filter factor was defined by referring to the crest factor method, and the time-varying perceptual weighting coefficient was determined based on the sequence relation analysis method, and the time-frequency filter network was established to weight the basic feature matrix and establish the impact sound quality evaluation index. Finally, based on the test data of the impact noise of the actual vehicle driving through the speed bump, the sound quality index was calculated, and comparative verification was carried out. The results show that the correlation coefficient between the proposed time-frequency perception weighted evaluation index and subjective evaluation is 0.927 at 20 km/h and 0.922 at 30 km/h. When considering the road impact acoustic time history evaluation, the correlation coefficient between the classic sound quality evaluation index(characteristic frequency band time-varying loudness) and subjective evaluation is 0.933 at 20 km/h and 0.649 at 30 km/h. The proposed time-frequency perception weighted evaluation method has good applicability for the conditions of 20 km/h and 30 km/h.