An On-site calibration method for on-line detection system of wheelset geometric parameters

摘要

Wheelset is one of the most important parts of the train, and the malfunction of the wheelset will directly affect the drivingsafety. Accurate and efficient wheelset geometric parameters detection is of great significance to the development ofrailway systems. Online measurement system using structured light is the current research hotspot, which has theadvantages of non-contact, fast speed, etc. This paper proposes an in-field calibration method that is with simple operation,high efficiency and high precision for the on-line detection system. Position of the feature points was obtained with theaccuracy of sub-pixel level. Considering two kinds of (radial and tangential distortion) distortions at the same time, theLM (Levenberg-Marquardt) optimization algorithm was used to obtain the nonlinear equations with the smallestcomprehensive error. Then the internal and external parameters of the camera are obtained. In addition, the method hasbeen applied to the site. High-precision result of wheel diameter which is obtained from on-line diameter inspectionequipment can be used to correct the situation when the structure light deviates from the center of the circle. The fieldmeasurements show that the error of the wheel pair parameters using this algorithm is within 0.3 mm and has goodrepeatability.