Riding Comfort Evaluation of Passenger Cars using Vibration Response of Human Body

Recently, the riding comfort of car passengers has become as important as the driving performance and the control stability. To improve riding comfort, it is necessary to evaluate comfort quantitatively and take increasing comfort measures. In this study, we analyzed the effect of vibration on riding comfort. First, we conducted a vibration experiment using ordinary sine waves with two different directions, X (fore and aft)-Z (vertical) and Y (lateral)-Z (vertical) in order to investigate vibratory sensibility in the high frequency range, 4.0-8.0Hz. The parameters of the input vibration were amplitude ratio and frequency. As a result, a dispersion was confirmed in each subjects' characteristics of vibratory sensibility. Then, in order to classify the subjects, a vibration experiment was conducted with single directions, X, Y and Z. We divided subjects into three groups from this result. Moreover, vibratory sensibility in each group was investigated using frequency and amplitude ratio as input conditions. In this result, adequacy of the grouping was verified. Furthermore, the discomfort tended to increase with increasing the amplitude ratio X (fore and aft)-Z (vertical) in each group.