THE RESEARCH ON THE LIMITED SPEED OF THE 4×4 OFF-ROAD VEHICLE ON UNEVEN ROAD

SUMMARY This paper, considering from the point of view of the effects of vertical vibration on the vehicle mobility,discusses the conditions of limited speed when 4×4 off-road vehicle traveling on uneven road. The criterion to evaluate the limited speed of off-road vehicles is developed. Five degree of freedom model of vertical vibration of the vehicle is established. The vibration responses of vehicle system are analysed in both time and frequency domains by means of computer simulation. The relationship between thecriterions and speed are established. The comparison of the road test results and the computer simulation results shows that there is a close agreement between them.This paper also discusses the influence of vehicle parameters on the limited speed for different road input and searches the approches to increase the limited speed. Also it provides a way to predict the limited speed and to optimige structure parameters of 4×4 off-road vehicle.