Research On Dynamic Of Vehicle-road Coupled System

With the increase improvement of highway transportation and the quick development of heavy road transportation, early damage of pavement, which is caused by the dynamic load of vehicles has become the outstanding problem in road design. The early damage of pavement will conversely arouse sharp increase of vehicle vibrations which will further severely affected the riding comfort and safety and Increase the dynamic load from running vehicle on the road surface at the same time. There is an interaction existing between the vehicle and road system, but the traditional vehicle-road system dynamics research is based on the vehicle dynamics and road surface dynamics, which take vehicle and road surface as two independent systems and didn’t fully consider the interact influence of vehicle and road. It does not reflect the real situation of vehicle and road. In order to simulate the work condition of vehicle-road system in a more realistic way, the interact influence of vehicle and road, which is based on vehicle-road system dynamics has been studied in this paper.Frist, In order to obtain the model of vehicle-road coupling dynamic system,Simplified model of vehicle subsystem, based on the simplified principle of vehicle dynamics is established and based on the analysis of forming mechanism of road structure,the physical model of the road subsystem is simplified and finally, through the contact relationship between vehicle and road(i.e. the coupling action between vehicle and road),the vehicle subsystem model and the road system model are unified.Second, through comparing of different mathematical algorithms, a new display integration algorithm proposed by Zhai Wanming and used to solve the nonlinear system dynamics equations is determined. Through the analysis of the algorithm theoretical derivation, the programming steps and flow chart which are used for solving the equation group by using of the software of Matlab are determined.On this basis, the characteristics of traditional vehicle-road system model are summarized. Furthermore according to the vehicle dynamic response and road dynamic response, the evaluation index of new and traditional vehicle-road coupled system dynamics model are proposed and compared.Finally, on the basis of verifying the vehicle-road coupled system dynamics model, the impact that different vehicle parameters(i.e., vehicle speed, vehicle load, front and rear wheels stiffness and damping, front and rear suspension stiffness and damping) and the road parameter(i.e., surface layer thickness, road grade, elastic modulus) on the road dynamic response is calculated and analyzed.