Research on rail end face slope algorithm based on Bisquare fitting

Abstract

The slope of rail end face needs to be measured by the base staffs before the rail is welded. Most of them are trained to manually measure, using a feeler gauge and an angle ruler. The measuring steps are complicated, making the whole process less than efficient and impossible to be applied at an automated pipeline inspection. This paper proposes a new type of non-contact rail end face slope measurement method, based on structured light vision system. Two structural light sensors are placed on the mechanical platform, specifically on the left and bottom of the rail, to obtain the contour data of the end and bottom surfaces. The data is transmitted to the host computer, while all contour data is converted into the same 3D world coordinate system. Next, the data is processed, using Bisquare fitting method. Finally, the end face slope result is obtained, by combining the mathematical descriptions of the end face slope. Experimental tests are conducted, proving that the proposed method of measuring the slope of the end face shows good stability and accuracy, while it can be used to complete the slope inspection of the rail end face, meeting the actual testing requirements.