Abstract: The difficulty of vehicle electronic control braking systems based on slip ratio control lies in identifying the optimal slip ratio of various roads. The dynamic loads caused by road roughness on uneven roads will bring fluctuations to wheel velocity, slip ratio, braking force coefficient, and influence on road identification indirectly. With the application of two empirical tire models, roads which vehicles run on are divided into 6 types and a road identification approach is proposed. A road characterization value which represents typical road characteristic parameter is built and 6 kinds of road condition characterization value intervals are given to identify the current road according to the closed area under the segment of braking force coefficient-slip ratio curve before optimal slip ratio. A vehicle dynamics model of 14-DOF including the excitation of road roughness is established, and the effectiveness of the approach is verified by the braking simulation tests on both an uniform road and a joint road. The simulation results show that the approach proposed can identify the current road on uneven roads accurately and quickly, the identification results can be used for the optimal slip ratio control in vehicle electronic control braking systems conveniently.

Key words: Characterization value, Road identification, Tire model, Uneven road