| With the rapid development of China's industrial system,high-precision mechanical parts gradually have more and more gaps.Screw workpiece is a common connecting part in the mechanical industry,which is widely used in industrial products.Due to the improvement of thread quality requirements,the external thread detection system develops rapidly.Because of the advantages of fast detection speed and high measurement accuracy,the external thread detection system integrated with vision plays an increasingly important role in the thread detection system.In this paper,by studying the detection method of external thread proposed by other articles,a new algorithm of correcting the inclined thread profile of cylindrical external thread axis is creatively proposed,and a set of detection system of cylindrical external thread is built according to the algorithm.Based on the analysis of the previous research results of machine vision thread detection system,it is found that when using machine vision technology to detect the image of cylindrical external thread,the axis of the actual cylindrical external thread is not vertically upward coincident with the axis of the theoretical cylindrical external thread,and there is an axis tilt between them,which seriously affects the accuracy of thread detection.In order to eliminate the axis tilt For the influence of thread quality testing results,this paper mainly studies the following contents:(1)In this paper,an in-depth analysis of the current status of domestic and foreign research on external thread detection technology,an in-depth investigation of the current axis tilt state during external thread detection,the analysis of the impact of the external axis detection axis tilt state on the detection results,and established of a cylindrical external thread with the axis tilt state mathematical model.(2)The machine vision imaging principle,the basic theory of thread detection shadow formation,the reason and influence of the thread detection axis tilt are studied,and a cylindrical external thread axis tilt tooth correction algorithm is creatively proposed.(3)According to the actual needs of thread inspection in the factory,the system was designed.Based on the hardware design and software architecture,a vision-based cylindrical external thread axis inclined tooth profile correction detection system was proposed.(4)The contrast enhancement algorithm,filtering algorithm,edge detection algorithm and edge morphology processing algorithm in the image processing process are studied,so as to pave the way for the subsequent correction of the contour of the cylindrical external thread profile.(5)A cylindrical external thread detection platform is designed.Through the experimental detection of cylindrical external thread workpieces of M6,M8,and M14,the accuracy of the cylindrical external thread axis tilt profile correction algorithm proposed in this paper is verified,and the cylindrical external thread axis tilting profile correction detection system can effectively improve the accuracy of cylindrical external thread detection. |
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