Steel rail contour real-time form identification and distortion calibration method based on three-layer matching

Abstract

The invention discloses a steel rail contour real-time form identification and distortion calibration method based on three-layer matching. The method aims at a problem of high difficulty for accurately identifying and calibrating contour distortion in high-precision dynamic detection on steel rail contour by means of laser displacement technology. The method comprises the steps of calculating a matching degree through constructing a three-layer matching area which is composed of a contour rail jaw point, a rail head linear area and a rail waist characteristic area, and comparing the matching degree with a statistics threshold, thereby accurately differentiating the measured contour form in real time; and aiming at an identified distorted contour, through preliminary alignment of the template contour and iterative optimization of the matching degree, obtaining an optimal affine transformation parameter for calibrating the distorted contour. Through experiments, the method effectively eliminates influence of vibration to measured data of the steel rail contour and furthermore improves contour measurement precision. Furthermore the method supplies a new though and a technical reference for popularization and application of laser displacement technology in high-precision dynamic detection on the steel rail contour.

Description

technical field [0001] The invention relates to the field of rail transit detection, and in particular to a real-time identification of whether the rail profile is distorted or deformed based on a two-dimensional laser displacement sensor for dynamic measurement of the profile, a new method for correcting the deformed profile, and the like. Background technique [0002] At present, the non-contact rail profile dynamic measurement system constructed by combining a line-structured laser light source and a CCD camera has been widely used in rail maintenance. The system is installed on the rail inspection car or the road-rail dual-purpose inspection car, and can directly measure various parameters of the rail section with the car body, which greatly improves the efficiency of maintenance operations. [0003] According to the different processing methods of CCD imaging data, the system can be divided into two types: laser video technology and laser displacement technology. [00...

AI Technical Summary

Problems solved by technology

Vibration in all directions is coupled with each other, it is difficult to directly measure

[0008] Among the 6 vibration forms, only nodding vibration and shaking head vibration cause distortion and deformation of the measurement profile, resulting in a decrease in detection accuracy

However, the laser displacement technology with higher detection accuracy can only obtain the two-dimensional digital coordinates of each sampling point on the measurement contour relative to the incident point of the light source, and cannot obtain the third-dimensional longitudinal coordinates of the track like the laser vision technology, so this problem has not been solved. can be effectively solved, which also limits the application of laser displacement technology in contour detection

The vertical coordinate difference between B and F is relatively large, and the horizontal coordinate difference is small. Only the contour deformation caused by the nodding vibration with a large change angle can be identified, and it is difficult to accurately identify other deformation contours (shaking head contours, mixed deformation contours) or small angle nodding silhouette

[0021] 2) The conventional two-dimensional contour matching method is difficult to calibrate

[0022] One is that the available feature points among the seven feature points from A to G are only two points, B and F, and the affine transformation parameters cannot be obtained by directly collecting three pairs of feature points;

[0023] Second, when affine deformation occurs to the measurement profile, the rail waists R400 and R20 change from circular arcs to elliptical arcs, the arc lengths are very short (the corresponding central angles are 12.3° and 65.9° respectively), and the surface contains noise. To fit five parameters such as the coordinates of the center point of the ellipse, the major and minor axes, and the inclination angle, the solution accuracy is low and it is difficult to meet the actual needs

[0024] 3) The measurement error introduced in the production process of the rail

Images