Study On Virtual Realization And Improvement Measure Of High-speed Automotive Cross-wind Response Characteristic

The high-speed, light-weight and streamline tendency of modern vehicle makes cross-wind stability gradually become one key problem which must be solved on active vehicle safety study. Road tests are usually with great danger and cost a lot of money. Furthermore, the testing results are prone to be influenced or restricted by subjective and objective factors. Whereas using computer to design, sample vehicles and test times can be minimized during the developing process. So there is great academic and practical value in the study of high-speed automotive cross-wind response characteristic and it's virtual realization.Both the quantitative analysis on vehicle performance and the development of advanced chassis control system depend largely on the precision of building dynamic model of vehicle and tire. In this thesis, the influence of aerodynamic forces on high-speed automotive handling and stability is discussed theoretically. Through the analysis of calculational instance, comparison about characteristic and superiority is stressed on Gim, Magic Formula, power exponent formulas and neural network tire model. The application of tire model in the cross-wind stability simulation is analyzed from the theory point of view. Taking an oversea vehicle as study object and using multi-body system dynamic theory, this thesis builds an automotive cross-wind response characteristic analytical model of rigid-flexible coupling multi-body system based on ADAMS/Car software platform, including the subsystem models of body, suspension, steering, tire and so on.Using multi-body vehicle model, the responses to crosswinds are simulated from the aspects of cross-wind sensitivity test, step input test of steering wheel angle and unsteady crosswind input test keeping steering wheel free. The simulation of cross-wind condition is well realized. During the simulation analysis, pressure center's shift is taken into account for the fist time. Through comparison with test data, the precision of vehicle model and the validity of simulation method are testified. Undoubtedly, the study offers a new way in the cross-wind stability domain. This thesis also presents some measures about improving cross-wind stability according to the results of simulation and parameter analysis.