基于机器视觉的冷油管螺纹中径自动检测系统

Thread s pitch diameter automatic measurement system based on machine vision

在冷油管接头螺纹中径的不良分拣检测过程中,因采用人工检测而存在检测准确率低、效率低下的问题,为此,提出了一种基于机器视觉的油管零件螺纹中径不良品分拣检测系统。首先,基于机器视觉的油管零件螺纹中径不良品分拣的方案,在三针法中径测量原理的基础上,提出了基于机器视觉的四针法的虚拟量针定位算法,并通过Hough变换获取了牙线直线,结合线切圆定位的方法,自动获得螺纹中径线,实现了对中径的自动测量;然后,以冷油管螺纹中径检测分拣评价标准为依据,进行了机器视觉系统的选型,完成了基于机器视觉的冷油管螺纹中径检测系统的总体设计,并结合机器视觉的螺纹中径检测控制系统的控制流程,完成了对控制程序的设计;最后,从系统检测精度和重复精度两方面出发,对基于机器视觉的冷油管螺纹中径检测系统的精度和分拣能力进行了验证。研究结果表明:系统可很好地对产品螺纹中径不良品进行筛选,且检测精度达到0.01 mm,重复性精度达到0.001 mm;该检测系统可为同类型产品的品质检测提供一种新的解决方案。

In the process of bad sorting detection of pitch diameter of cold oil joint thread,the detection accuracy and efficiency are low due to manual detection.Aiming at the problem,a sorting detection system of bad pitch diameter of oil pipe part thread based on machine vision was proposed.Firstly,in the pitch diameter detection model of machine vision detection,based on the principle of three needle pitch diameter measurement,the virtual measuring needle positioning algorithm of four needle method based on machine vision was innovatively put forward.The algorithm obtained the straight line of dental floss through Hough transform,combined the method of tangent circle positioning to automatically obtain the pitch diameter of the thread,and realized the automatic measurement of pitch diameter.Then,the machine vision system was selected based on the evaluation standard of the cold oil pipe thread,the overall design of the cold oil pipe thread diameter detection system based on machine vision was completed,and the control program process of the machine vision was completed too.Finally,the system detection accuracy and repetition accuracy were measured.The experimental results show that the system can screen the pitch diameter of the thread of the product,the detection accuracy is 0.01 mm and the repetitive accuracy is 0.001 mm,which provides a new solution and special machine design for the quality inspection of the same type of products.