Geometrical Error Online Measuring System For Sucker Rod

Geometric error seriously affects the quality of sucker rod.There are mainly two methods to detect the Geometric error of sucker rod,which are manual detection and off-line instrument detection.There are problems such as inconsistent detection results and low detection accuracy in manual detection.The off-line geometric error measuring instrument is difficult to be applied to the production line.In this paper,a online detection system is developed,in order to solve the problem of measuring the geometric error of sucker rod.Through the analysis of the actual situation of industrial field and the requirements of inspection,this paper designed a detection scheme of laser triangulation method,calculated parameters of laser displacement sensor and designed mechanical structure for the detection.Software is developed by LabVIEW to debug this system.The operator for geometric error detection is designed.A model-based gross error eliminating method is constructed using a robust fitting method of random Hough transform;a filter is designed to filter the measurement data;the spindle error is compensated based on robust fitting model using coordinate transformation;through analyzing the advantages and disadvantages of least square circle method,minimum zone circle method,maximum circumcircle method and minimum inscribed circle method,algorithm for solving minimum zone circle is proposed based on least squares and valid point set,greatly improving the efficiency of solving the minimum zone circle.Algorithm and software of the detection system are coded using C#programming language.This detection system is debugged in the industrial field,and is installed on the production line.