Fractal surface roughness Reconstruction Method

In the field of vehicle engineering, road roughness, vehicle major factor in the operating environment is the main incentive vehicles and vibration sources, the road uneven to produce vehicles in the driving resistance and vibration, driving resistance and the power consumption of vehicles, vehicle power system and transmission of life. In road engineering, road roughness is also the assessment of quality of domestic and international road project one of the indicators, roughness testing quality testing throughout the road construction, evaluation, inspection and operation of the quality of inspection and maintenance of roads and other areas. Study of roughness, a reasonable model of vehicle road reconstruction and road engineering works are of great significance. This paper focuses on the fractal characteristics of road roughness, road roughness fractal modeling techniques conducted in-depth and systematic research. Specific tasks are as follows: The surface roughness of the acquisition system of a non-contact laser roughness detector structure and principles, and gives a laser roughness detector part of the typical path of measured road roughness data.Then the road roughness data measured power spectrum analysis, the results indicate that road roughness has obvious fractal characteristics of that scale (spatial frequency) and measurement (power spectrum) in double logarithmic coordinates is linear.Different fractal dimension than the analysis of calculation methods, the results show that the standard scale used for the power spectrum method and calculate its fractal dimension; the actual road, the root mean square method based on the accuracy of the stability of the fractal characteristics of the study should be used when both root method.Classification by surface roughness map analysis found that the fractal dimension is not the only state to determine whether a road surface roughness, the fractal dimension in the characterization of surface roughness measured in the presence relative.Classification by analyzing the road rules when calculating the root mean square method and found that the road can be used for the standard level of fractal dimension and the only road roughness coefficient to characterize road roughness, and for measured road roughness, are advised to use fractal fitting a straight line dimension and the intercept on the vertical axis to the characterization of the only road roughness. Proposed use of the ideal fractal curve of road roughness for one-dimensional reconstruction. Ideal fractal curve by solving the fractal parameters were measured on the standard scale road and the road was one-dimensional reconstruction, by contrast, and relative power spectrum error analysis shows that the establishment of one-dimensional model of high precision surface roughness. For the two-dimensional reconstruction of road roughness using fractal Brownian motion based on the random midpoint displacement fractal interpolation algorithm parameters and by solving the road variance, respectively, and a standard level and the actual road pavement reconstruction model, and through any vertical section of the power spectrum compared with the target power spectrum and the relative error analysis shows that the establishment of the two-dimensional reconstruction of road roughness statistical properties of the model close to the target can be a very good statistical properties of road roughness, the model accuracy.

 

Keywords: Reconstruction of road roughness, road test the system spectrum, fractal theory, the ideal fractal curve, fractal Brownian motion