Design And Research Of Spot Welding Measurement System For Y-type Pipe Joint Group Based On Vision

Y-type pipe joint is a type of intersecting pipe commonly used in mechanical,petrochemical,and pipeline engineering.The size of the gap between Y-shaped pipe joint pairs directly affects the quality of subsequent spot welding.Currently,the gap size is mostly measured manually,which cannot meet the accurate and fast measurement requirements for gap size under the trend of intelligent manufacturing.Since the weld seam of pipe joints is in the form of an intersecting line,it is relatively complex to achieve automated spot welding.To address these issues,this paper uses the measurement of Y-type pipe joint pairs as an application scenario of visual detection technology and develops a Y-type pipe joint spot welding visual measurement system.The specific research contents are as follows:(1)The overall scheme design of the visual measurement system and the construction of the spot welding prototype.After analyzing the process of spot welding Y-type pipe joint pairs,the allowed error range of gap size and welding method are determined.The mathematical model of the intersecting line weld seam is established,and Matlab software is used to simulate the mathematical model and complete the selection of spot welding positions.The overall scheme of the measurement system is proposed,and the model is established using Solid Works software.A physical prototype and a measurement experimental platform are constructed,and the hardware selection of the motion control module and the visual measurement module is completed.(2)Y-type pipe joint measurement system calibration and image preprocessing.The camera calibration principle and the different coordinate system conversion processes in camera imaging are studied,and camera calibration experiments are completed using Matlab toolboxes.Based on the weighted average method,the gray-scale image of the gap between the pipe joint pairs is processed,and different filtering algorithms are used to filter the noise of the gray-scale image.According to the filtering effect,the median filtering algorithm is determined to implement image denoising.By analyzing the morphological processing algorithm,the morphological erosion and dilation operations are selected to remove edge burrs in the image,and it is proven that good gap stripe images can be obtained.(3)An improved Canny edge detection algorithm is proposed.In response to the problems of missing image details and poor adaptability of artificial threshold selection in traditional Canny algorithms,the algorithm is improved by incorporating multiscale detail enhancement and Otsu adaptive threshold segmentation,which can achieve adaptive extraction of edge features.By establishing the geometric relationship between the fringe break point and the intersecting line weld,a method for measuring the clearance of Y-type pipe joint was proposed.The absolute difference value between the gaps on both sides of the pair is used to measure the centrality of the pair,which is compared with the evaluation standards to achieve intelligent judgment of the quality of Y-type pipe joint pairs.(4)Software interface development and error analysis of the Y-type pipe joint pair gap measurement system.The software design requirements are analyzed,and the overall framework of the software is constructed.Based on the Pycharm and Pyqt development environment,the human-computer interaction interface design of the measurement system software is completed.Finally,factors affecting the measurement accuracy are analyzed from the aspects of imaging system,adjustment,and workpiece processing.In summary,this paper focuses on the visual measurement of Y-type pipe joint spot welding,proposes an overall scheme for a visual measurement system based on Y-type pipe joint spot welding,and realizes edge extraction,gap size measurement,and intelligent judgment of pair quality.The proposed method has important significance for improving subsequent welding quality.