车辆自适应巡航控制的内秉模态特性

Intrinsic modal characteristics of vehicle adaptive cruise control

为分析车辆自适应巡航控制下的跟驰状态对驾乘舒适性的影响,基于刺激-反应类线性跟驰模型,分别模拟跟驰车在微尺度避撞工况、微尺度扰动工况和全球统一轻型车辆测试循环(world light vehicle test cycle, WLTC)工况的速度-时间图像,采用经验模态分解(empirical mode decomposition, EMD)和快速傅里叶变换(fast Fourier transform, FFT)相结合的时频分析方法提取跟驰车的内秉模态特性,分析低频下不同驾驶工况对驾乘人员舒适性的影响。结果表明:不同驾驶工况的内秉模态频率不同,频率越小,车辆的振幅越大;相较于微尺度避撞工况和扰动工况,WLTC工况的内秉模态频率带宽分布较宽,幅值较高,波动能量较大;WLTC工况下,频率小于0.10 Hz的超低频区的内秉模态幅值较高,人体恶心程度较严重,对运动病的贡献较大。

To investigate the influence of car-following status on driving comfort,a stimulus-response linear car-following model is used to simulate the speed trajectory of the following vehicle under the working conditions of microscale collision avoidance behavior,microscale disturbance behavior,and the world light vehicle test cycle(WLTC).A time-frequency analysis method combining both the empirical mode decomposition(EMD)and fast Fourier transform(FFT)is adopted to extract the intrinsic modal characteristics of car-following behavior,and analyze the impact of different driving conditions on the comfort of drivers and passengers at low frequencies.The results show that the frequency of the intrinsic modal is different in different driving conditions,and the smaller the frequency is,the greater the amplitude of the vehicle is.Compared to the microscale collision avoidance condition and disturbance condition,the frequency bandwidth distribution of the intrinsic vibration mode in the WLTC condition is wider,and the amplitude is also higher with larger fluctuation energy.Under the WLTC working conditions,the amplitude of the intrinsic modal in the ultra-low frequency range with the frequency less than 0.10 Hz is higher,and the degree of nausea in the human body is more severe,which makes a greater contribution to motion sickness.