Abstract: Reasonable road texture features can better reflect the anti-slip performance of road surface and Tire/Road contact characteristics. Based on fractal theory, a three-dimensional road surface reconstruction method is proposed in this paper. According to the national standard, the time domain expression of two-dimensional random pavement spectrum is given. The box dimension is used to calculate the fractal dimension. The traditional two-dimensional road spectrum is extended to three-dimensional pavement by using the random midpoint displacement and the fractal Brownian motion principle. Taking a typical bump as an example, the special excitation is incorporated into a flat road surface with detailed texture. The application of 3D pavement spectrum in vehicle multi-body dynamics software is realized by compiling in the TruckSim software. By comparing the vehicle dynamics response under the two-dimensional road spectrum and the three-dimensional road spectrum, it is found that the vertical force and the longitudinal force have little difference and have good consistency. But the lateral force difference is relatively large, indicating that the established three-dimensional road surface spectrum has the better accuracy and reflects the three-dimensional texture characteristics of the road surface. It provides a basis for vehicle curve passing performance and vehicle rollover control research.

Key words: road surface texture, fractal theory, random midpoint displacement method, Brownian motion, three-dimensional road spectrum