Research On New Type Of Pipe-end Rectification Equipment And Technology Based On Machine Vision

Pipeline transportation is an indispensable mode of transportation in modern society.However,the existence of the butt weld defect caused by the ellipticity of the pipe-end is one of the main reasons for the failure of the pipe,therefore,we need to rectify the end of the pipe which is not qualified for ellipticity.At present,the commonly used methods of straightening are: mechanical diameter expanding,diameter fixing,over-bending,rolling bending,etc.In this paper,the over-bending straightening process was studied and a new type of pipe end straightening equipment based on machine vision was designed.The main research contents include:First of all,according to the characteristics that the circumferential dimensions of pipe fitting are not changed by the over-bending straightening circle and the bulging theory draws the conclusion that the wall thickness of pipe fitting remains unchanged before and after the over-bending straightening circle.Then,finite element software MSC.Marc is used to simulate the straightening process of the whole pipe and long pipe end of large pipe fitting,and analyze the deformation characteristics and stress distribution during the straightening process.By comparing the elastic recovery law of the whole pipe straightening circle and the long pipe end straightening process,it is concluded that the undeformed area will affect the rigid end of the pipe end straightening process.Through the simulation of the relationship between ellipticity and relative diameter enlargement after unloading,the appropriate control strategy of the inner bracing overbending rectification circle is formulated to provide theoretical guidance for the straightening process of pipe fitting rectification.Secondly,by changing the parameters of pipe fitting and mould,the influence of the parameters of pipe fitting and mould on the course of bending and rounding is obtained.Thirdly,the structural design of the leveller and the selection of its main components are completed.The finite element software ANSYS Workbench was used to conduct strength check on key parts.Finally,the design of machine vision system for pipe end identification of pipe fitting is completed.Choose a reasonable image acquisition device,develop a reasonable image processing process,and choose appropriate camera calibration method and ellipse fitting method,then MATBLE software was used to process the pipe end images taken according to the established image processing process,which verified the feasibility of the visual system.The feasibility of the straightening strategy was verified by using the straightening strategy.