基于分形理论的三维路面谱重构及在多体动力学软件中的应用

Reconstruction of Three-Dimensional Pavement Spectrum Based on Fractal Theory and Its Application in Multi-Body Dynamics Software

合理的道路纹理特征可以更好地反映路面抗滑性能和轮胎/路面接触特性。基于分形理论提出了一种三维路面谱重构方法。依据国标给出二维随机路面谱的时域表达,利用计盒维数法计算各级路面分形维数,综合应用随机中点位移法和分形布朗运动原理将传统二维路谱拓展为三维路面谱。以典型的减速带为例,将特殊激励同构到含有细节形貌的平整路面谱中。在TruckSim软件中通过编译实现三维路面谱在车辆多体动力学软件中的应用。通过对比二维路谱和三维路谱下车辆动力学响应发现:垂向力和纵向力差异不大,有较好地一致性,但侧向力相差比较大,表明所建立的三维路面谱有较好精度的同时反映了路面的三维纹理特性,为车辆曲线通过性能和车辆侧翻控制研究提供了基础。

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.