Research On Straightness Detection Method For Inner Hole Of Long Tube Straightening

In general,tubular parts with a length to diameter ratio greater than 5 are collectively referred to as long tubes.This type of part is characterized by a large ratio of hole length to bore diameter,and the inner hole is the key face of the part.Because of this,the straightness of the long hole of the long pipe is often used as one of the key criteria for the acceptance of such parts.Although there are currently some devices and solutions for detecting the straightness of the bore,they are not suitable for long tube straightness detection.Therefore,the straightness detection method of the inner tube hole in this paper will be applied to the straightening process,and it will be used together with the straightening equipment to lay the foundation for the automatic alignment of the long tube inner hole.In addition,in order to follow the requirements of project,the gun barrel was selected as the research object.Based on the existing deep hole straightness detection research and the working characteristics of the straightening machine,this paper proposes a new optical axis long tube straightening inner hole straightness detection method using CMOS camera.And designed and researched a set of effective barrel straightening straightness detection system,which can be used to automatically detect the straightness of the inner hole of the barrel.In addition,the inspection program can also be used for the inspection and alignment of other long tube parts.Firstly,the proposed scheme solves the problem that the self-centering mechanism of the existing detection method introduces the detection error when it rotates during the moving process.Secondly,according to the proposed detection method,the straight line of the barrel alignment hole is designed in detail.The degree detecting device,including the worktable,the driving mechanism and the imaging system,specially designed a novel self-centering mechanism capable of detecting the straightness of the barrel with the rifling,the structure is simple,the assembly error is small,and the centering mechanism can be reduced The introduced error;then,the processing flow of the image is designed,which can stably and accurately obtain the coordinates of the center point of the long hole.The experiment based on the detection scheme in this paper was designed.Through data acquisition and analysis,an error compensation method is proposed.After error compensation,the absolute error of the detection result of this scheme is controlled within ?0.006 mm.Finally,the program of long tube straightening straightness detection system is compiled by C# and Halcon programming language,including image acquisition,image processing and camera calibration.Five parts,such as straightness solution and data storage.Through the above design and research,the hardware and software of the entire long tube straightening inner hole straightness detection system are completed.In the experimental verification,a ?30 ?1500 mm barrel was repeatedly tested,and the detection repeatability of the detection system was verified.The repeatability was within 0.015 mm.The long tube was detected by detecting the straightness error.The accuracy of the detection system is verified,and the accuracy is within 0.02 mm.Finally,an error analysis is performed on the detection scheme.Based on the above analysis,the detection system can meet the requirements for straightness detection of long tube alignment.