Abstract: A dynamic vibration model with twelve degrees-of-freedom of vehicle-human system was established for the light-duty bus SY6480. A road excitation with the correlation of four wheels and a human body model were included in the vehicle model. The dynamic equations were derived from the system energy equations,and vehicle-human system vibration simulation in time domain as well as experiment verification was carried out. The comparisons show that obtained simulation results are more accurate than those calculated from the conventional linear method in frequency domain. Furthermore, the spectral analysis on the sample vehicle shows that the angular vibration energy is about one-fourth of that in vertical vibration of the vehicle, so that cannot be ignored in vehicle vibration study, and the vertical eigenvibration of human body has a resonant frequency of 2.0～2.5 Hz, which may be a reference for vehicle ride comfort design.

Key words: vehicle engineering, vehicle-human system, random vibration, time domain simulation, spectral analysis