Intrinsic modal characteristics of vehicle adaptive cruise control
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.