Dynamic Calibration Technique For Wheel Set Wear Online Measurement

In the railway operation system, wheel set is one of the most important factors for trainrunning safety. The condition of wheel set is directly related to the safety of train running. Therefore,wheel set wear measurement is an important measure for ensuring the safe running of train.This paper analyzes the domestic and calibration techniques based on the oblique light-wheelwear detected by the basic principle, the use of a line structured light and image sensor line detectorcalibration wheel of the new method of wear, complete camera calibration and dynamic calibrationof the detection process. The main contents of this paper are:(1) according to wheel wear line detection principle, a perspective based on the principle of thepinhole camera model calibration is presented. The transformational relation between physicalcoordinates and pixel coordinates was determined according to the actual camera pinhole model.The space angles and object distance of camera were calculated by iterative calculation method. Thecamera parameters provided calculation method for acquiring the wheel set wear parameters fromwheel set image. At the same a dynamic calibration method of entire measuring process wasproposed according to the online feature of wheel set wear measurement. The linear relationbetween wheel set base point and trigger position was determined according to wheel set motionmodel. According to the actual pixel coordinates of wheel set base point, the deviation of triggerposition was obtained by iterative calculation. The deviation value was used to correct the acquiringmoment in wheel set wear measurement process.(2) Design a dynamic calibration system, including desing the ccd asynchronous reset delaytrigger, locomotive speed and image acquisition .(3) According to the proposed dynamic calibration method, calibration system softwaredesigned to achieve a proximity switch parameter calibration process the amendment.Finally completed the experiments show that the calibration accuracy of 0.2mm, wheel wear tomeet the accuracy requirements for online testing.