Study On Profile Measurement Of Wheel And Rail Based On Laser Scanning

Precision testing occupies an important position in the field of modern industry,and is widely used in dimension testing,mold modeling and other aspects.With the rapid development of photoelectric information,laser,image recognition and other technologies,the limitations of traditional clamp contact detection have gradually emerged.In recent years,the non-contact detection technology represented by laser scanning has been rapidly developed and widely used in many fields.There are two ways of two-dimensional contour measurement based on laser scanning.One is that the point laser combined with translation or rotation and other mechanical motion can complete the contour scanning,but it is difficult to meet the requirements of irregular contour scanning.Secondly,the line laser combined with the camera can complete the scanning of the contour,which can be used for the scanning of the irregular surface contour,but its accuracy is lower than the point laser scanning method.During the train operation,the rolling and friction of the wheels on the rail will cause serious wear on the contact surface of the two,which will affect the smooth operation of the train and lead to major safety risks such as derailment.Therefore,accurate and efficient measurement of the contour of the wheels and rail is of great importance for the safe operation of the train.In this paper,combining the above two laser scanning methods,The application of point laser and line laser scanning in wheel tread profile and rail surface profile measurement and profile visualization technology are mainly studied.A point laser displacement sensor with an accuracy of 0.05 mm was used for mechanical scanning of the contour of the wheel tread,and a magnetic grid displacement sensor was used to provide axis displacement coordinates for the scanning process.After the scanning,the two-dimensional coordinates of the contour were obtained,and geometric parameters such as rim height,rim thickness,QR value and rim width were calculated.The paper analyzes and compensates the existing errors.After the compensation,the repeatability error of the system is less than 0.05 mm,and the measurement error of each parameter is less than ±0.1mm.Rail profile measurement using laser scanning,laser stripes were collected for camera,image noise,setting up ROI,in turn,to go to area,extraction of laser stripe center pixel coordinates and image processing operations such as get rail outline,namely carries on the outline according to the definition can be obtained after registration parameters such as vertical abrasion,side abrasion,always wear;Through the repeatability experiment,the repeatability error of the system is less than 0.03 mm,and the measurement error of each parameter is less than ±0.1mm.The paper analyzes the errors of the system.In summary,the main work of this paper is as follows:1.This paper introduces the research background,significance and research status at home and abroad.2.The wheel tread profile was obtained by point-based laser scanning,and its profile parameters were calculated.The measuring principle and hardware design are introduced,and the calculation method of each parameter is given.3.Line laser scanning method is adopted to obtain the rail profile and calculate its wear value;The measuring principle and hardware parameters are introduced.The image processing algorithm and contour registration scheme are discussed in detail.4.Based on Android platform,write special software for rail profile detector and special software for wheel profile detector to realize contour measurement visualization.5.Repeated experiments were carried out to verify the feasibility of the scheme;And the error of the instrument is analyzed.