Track Detection And Adjustment Algorithm Of Curve Based On Laser Scanning Technology

The detection and maintenance of existing railway is an important means to ensure the smooth, comfortable and safe operation, and the high standard of the line requires a high precision, full range of line detection methods. Three-dimensional laser scanning technology with its all-weather, high information, does not interfere with the traffic characteristics get applied to existing railway retesting, but three-dimensional laser scanning data in track detection application, there are still a lot of technical problems need to be solved. In this paper, take existing railway curve adjustment problem as the main study object, start from the curvature and curvature changing rate based on the point cloud information, curve reconstruction, further study of the following aspects:1) Research on the application method of three-dimensional laser scanning technology in the field of existing railway retesting.Study on the equipment selection of three-dimensional laser scanning that can be used in existing railway retesting. According to the data analysis and in-site investigation, we recommend using high-precision phase scanners,font scan mode as “?” and outside survey with no more than 50 m spacing. Combined with the measured data, verify the feasibility of survey programs through the point cloud data processing, data extraction circuit characteristic the feasibility and accuracy analysis.Introducing Three-dimensional laser scanning technology into the existing railway retesting, using the field measurement data acquisition of high efficiency, complete data and can realize continuous measurement, analysis on the characteristics of point cloud data processing, line data extraction and precision analysis verify the feasibility of the technology applied in the existing reiteration.2) Analysis of curvature and curvature changing rate under different measured points spacing conditions.According to the point cloud data obtained by using three dimensional laser scanning technology, the curve fitting of the existing railway is realized by using three spline curves, the curvature and curvature change rate of 20 m, 10 m and 5m under different measuring points are obtained. The analysis found that under the condition of the change rate of curvature with 5m measurement interval can better reflect the continuous changing features of track structure, and 5m chord can be used in high standard curve line state detection and adjustment. At the same time, combined with the curve design and testing standards, analyzes the curvature variation of root that static and dynamic detecting standards are not uniform.3) Research on the curve parameter reconstruction algorithm based on point cloud data and its application.Get coordinates under different spacing line based on the point cloud data, considering the changing process of the measuring points of the plane coordinate(x, y), design the plane linear fitting method based on orthogonal least square principle, obtain the initial parameters of line by the curvature feature near the ZH and intersection, achieve optimal reconfiguration of plane curve by iterative calculation. Reconstruct the curve parameter and calculate the plane adjustment amount under 20 m,10m,5m measured point spacing combining with specific data, finally found that the 10 m and 5m chord in the calculation of the measured results of calculating point plane adjustment is significantly more optimal than that of the 20 m chord, also in accordance with the requirements of 5m chord at the passenger line curve state detecting.