Research On The Technology Of Measuring Shaft Diameter With Linear Structured Light Vision

Shaft is one of the most common parts in the mechanical transmission system,the shaft diameter is an important indicator for evaluating shaft machining accuracy.Its machining precision directly affects the performance of the whole machine.With the rapid development of modern manufacturing industry,higher demands are placed on fast and accurate measurement of the dimensions of shaft parts.This article focuses on shaft components and conducts research on line structured light visual measurement of shaft diameter technology.The main research content is as follows:(1)On the basis of analyzing the existing non-contact measurement technology of shaft parts,measure the shaft diameter by using the line-structured optical vision system composed of laser line light source and camera,study the establishment of the shaft diameter measurement model according to the light strip information on the surface of the shaft,and check the accuracy and measurement precision of the shaft diameter measurement model through experiments.(2)According to the calibrated line-structured optical vision 3D measurement system,the light strip curve on the surface of the measured shaft is represented on the optical plane using standard elliptic equations.The transformation relation between the camera coordinate system and the measurement coordinate system on the light plane is determined by calibrating the measured shaft.Finally,the geometric fitting ellipse to measure the shaft diameter is modeled based on the minimum of the sum of squares of the distances from the center point of the light strip to the perpendicularly corresponding points on the shaft surface.(3)Based on the coordinates of the center point of the light strip on the detected shaft surface,the perpendicular counterpart on the elliptic equation of the light strip is determined by iterative calculation.An algorithm for geometrically fitting the elliptic measurement shaft diameter is given using Newton’s iterative formula.Using the center point of the light strip data,test calculations were performed on the algebraic and geometric fitting elliptic measurement shaft diameter,and the results show that the error of the geometric fitting ellipse measurement shaft diameter is not only smaller than that of the algebraic fitting ellipse measurement,but also more stable.(4)Through experiments to analyze the noise of the shaft surface light strip image,an improved noise reduction method combining median filtering and Gaussian filtering is proposed,and the results of image measurement show that the improved filtering algorithm can effectively reduce the influence of image noise.Detecting the center point in different areas of the light strip image of the shaft surface to measure the shaft diameter,the results show thatdetecting the center point close to the main point of the camera and in an area where the light strip is less distortedconducive to improving the accuracy of the shaft diametermeasurement.(5)The corner image of the chessboard calibration board was used as measurement data to eliminate the influence of point detection errors in the light bar image,and the accuracy of the geometric fitting ellipse measurement axis diameter algorithm was evaluated.By using static and dynamic line structured light vision to measure the diameter of a stepped shaft,the effectiveness of the improved filtering algorithm in image denoising is tested.The influence of the spindle speed of the machine tool and the material of the measured shaft on the accuracy of line structured light vision measurement of shaft diameter is experimentally studied,and the main factors affecting the accuracy of line structured light vision measurement of shaft diameter are analyzed.