基于数学形态学的包覆层表面缺陷检测方法

包覆层表面缺陷的检测是保证发动机装药质量的重要手段。针对采集的包覆层表面缺陷图像,利用数学形态学的顶帽与低帽变换相结合的方法进行了缺陷特征增强,采用高低阈值的方法实现了缺陷图像的分割,得到了二值化图像,并通过中心半径标定,得出了有效检测区域,计算出了缺陷的大小和位置,检测结果表明,该方法的位置检测精度小于0.4 mm,检测分辨率可达到Ф0.5 mm,尺寸检测精度小于0.2 mm。     

微小尺寸零件表面缺陷光学检测方法

为实现微小尺寸零件表面缺陷的快速精确检验,对微小尺寸零件表面缺陷光学检测技术进行了研究.以典型微小尺寸环形零件为研究对象,从零件的表面特征、缺陷类型及检测算法出发,建立了基于机器视觉的微小尺寸零件表面缺陷光学检测系统;通过对微小尺寸环形零件表面缺陷纹理特征研究,提出图像梯度方差加权信息熵算法抑制表面随机纹理,提取微观表...     

基于机器视觉的弹壳表面缺陷检测系统设计

针对落后的检测枪弹外观品质工艺,利用机器视觉技术,设计了包含基于线阵相机的图像采集方式、缺陷分割算法以及缺陷分类算法的一套完整的解决方案。试验表明,该方案能准确实现对缺陷的分割和分类。     

陶瓷球表面缺陷图像检测及球面展开机构的研究

陶瓷轴承球的表面缺陷会严重降低球的强度和滚动接触疲劳寿命。针对陶瓷球表面缺陷自动检测要求精度高、可靠性高的特点,建立了基于图像处理的检测方案,并证明了该方案的有效性。为保证表面不漏检,应用螺旋面展开法设计球面展开机构,推导球面展开运动方程,计算转速控制曲线,分析了控制参数对检测系统精度和检测效率的影响,为陶瓷球表面缺陷自动分类和识别提供了可靠方法。     

圆柱体表面缺陷检测的ANSYS仿真

采用交变磁场测量的圆柱体表面缺陷的ANSYS仿真,以各向同性铝圆柱体为试件,采用柱坐标系及矩形激励线圈,电流流向为圆柱体轴向.将圆柱体体划分后再对各分体局部网格划分.划分较密的缺陷部分向周围划分较疏部分过渡时,采用四面体自由划分衔接.对带有表面周向缺陷的圆柱体网格划分后,产生的单元类型为四面体与六面体的混合.其仿真采用波前求解器.仿真路径为激励线圈沿缺陷长度方向、经过缺陷中心点进行周向移动.     

氮化硅陶瓷球加工缺陷分析与无损检测技术研究

氮化硅陶瓷轴承球具有优良的综合机械性能,在航空、航天等领域有广泛的应用前景。然而在陶瓷球加工的各个阶段都能产生表面缺陷,处于表面和次表面的加工缺陷能显著降低陶瓷球的疲劳寿命。本文综述了陶瓷球的加工方法、加工缺陷的形成与扩展及其无损检测技术的研究进展。制造高强度结构陶瓷的关键是避免材料制备过程中形成的缺陷,球坯材料的显微结构、材料缺陷和机械加工工艺参数对成品球的质量有显著影响。国内外采用射线检测、超声波检测、渗透检测、激光散射等多种方法进行陶瓷球表面缺陷检测研究。由于陶瓷球表面缺陷具有多样性且球表面不可展开,至今还没有完善的无损检测方法。     

基于BP 神经网络的弹壳表面缺陷分类方法

为了对弹壳表面缺陷进行分类,提出一种基于BP(back propagation)神经网络的弹壳表面缺陷分类方法。针对弹壳缺陷的特点,提取了各类缺陷的灰度特征、形状特征、几何特征,建立缺陷特征数据库,并采用改进的BP神经网络算法设计了缺陷分类器。实验结果表明,该方法在枪弹缺陷识别方面具有很好可行性和有效性。     

基于BP 神经网络的弹壳表面缺陷分类方法

摘要：为了对弹壳表面缺陷进行分类,提出一种基于BP(back propagation)神经网络的弹壳表面缺陷分类方法。 针对弹壳缺陷的特点,提取了各类缺陷的灰度特征、形状特征、几何特征,建立缺陷特征数据库,并采用改进的BP 神经网络算法设计了缺陷分类器。实验结果表明,该方法在枪弹缺陷识别方面具有很好可行性和有效性。     

焊接药筒环焊缝缺陷超声检测方法

结合多年科研工作，提出了焊接药筒环焊缝的超声正交扫描探伤方法，并研究了每组探头工作方法和整体检测检测系统的设计方案。     

一种基于自适应阈值的弹壳表面缺陷分割方法

由于材料表面不均匀和基于线阵相机采集图像的方式,图像的目标和背景的成像效果是动态变化的,不能用单一固定的阈值进行弹壳表面缺陷分割。针对该问题,结合弹壳表面图像的特点和灰度直方图峰值特性,提出了一种自适应确定阈值的方法,试验结果表明该方法对能准确对弹壳表面缺陷进行分割。     

Automatic Detection of Steel Bali＇s Surface Flaws Based on Image Processing

A new method to detect steel bali＇s surface flaws is presented based on computer techniques of image processing and pattern recognition. The steel bali＇s surface flaws is the primary factor causing bearing failure. The high efficient and precision detections for the surface flaws of steel ball can be conducted by the presented method, including spot, abrasion, burn, scratch and crack, etc. The design of main components of the detecting system is described in detail including auto-matic feeding mechanism, automatic spreading mechanism of steel ball＇ s surface, optical system of microscope, image acquisition system, image processing system. The whole automatic system is controlled by an industrial control computer, which can carry out the recognition of flaws of steel bali＇s surface effectively.     

Processing Defect Analysis and Nondestructive Evaluation Technology for Si_3N_4 Bearing Ball

Researches on the processing method of ceramic bearing ball,the formation and propagation of defects in the manufacturing and the nondestructive evaluation（NDE） are summarized in this paper.The key for successful processing of high strength ceramic balls is to avoid producing related defects.Many investigations show that the material microstructures,defects as well as mechanical processing parameters influence the final surface quality significantly.Most of NDE technologies,such as radiation,ultrasonic,dye-penetration and laser scatter,have been studied for ceramic bearing ball surface inspection around the world.So far,the difficulties to develop the perfect NDE system for ceramic bearing balls,which are caused by the defect variety and surface unfolding,have not been overcome yet.     

Dynamic Analysis of Flexible Cage of High-speed Angular Contact Ball Bearing

A dynamics formula was established for the flexible cage of high-speed angular contact ball bearing. A modified Craig-Bampton component mode synthetic method was used to establish the formula with regard to the flexibility of cage and based on a dynamic analysis of angular contact ball bearing,and a rigid-flexible multi-body dynamic analysis program was developed using ADAMS,which is verified by a computation example of Gupta. The results show that it’s not likely to keep the rotation smoothness of cage when the ratio of pocket clearance to guiding clearance and the ratio of radial load to axial load become too large or too small. By comparison,the flexible cage runs more smoothly than the rigid cage.     

高速角接触球轴承保持架柔体动力学分析

在角接触球轴承动力学分析基础上,结合轴承保持架的柔体性,采用修正的Craig-Bampton子结构模态综合法建立高速角接触球轴承保持架柔体动力学方程.利用ADAMS系统开发了角接触球轴承刚柔多体动力学分析程序,对高速角接触球轴承保持架动态性能进行了分析;并采用Gupta的角接触球轴承动力学分析结果加以验证.分析结果表明...     

一种基于高阶曲面拟合的图像边缘检测方法

提出一种基于高阶曲面拟合的边缘检测方法,首先对图像进行自适应Wiener滤波,然后用一个邻域内的像素点来拟合一个高阶曲面,由此计算该点的梯度值,再依据梯度方向对梯度值进行抑制,最后依据统计特性选取阈值,得到边缘图像.仿真实验表明,该方法计算梯度准确,定位精度较其他方法更高,适合各种类型的边缘.     

Contact Force Distribution and Static Load-carrying Capacity of Large Size Double Row Four-point Contact Ball Bearing

Clearance not only affects the startup torque, rotation precision and stiffness of bearing, but also affects the load distribution, load-carrying capacity and life of bearing. A computational model in which the clearance of bearing is that included is presented for detennining the contact force distribusion and stric load-carrying capacity of a double row four-point contact ball bearing which is subjected to the combined radial, axial and overturning moment loadings. The relation between the negative axial clearance and the contact force distribution is analyzed. The static load-canying capacity curvesthe established, and the effects of the changes in negative axial clearance, curvatthe radius coefficient of raceway groove and initial contact angle on the static load-carrying capacityse analyzed. The results show that, with the increase in the absolute value of negative clearance, the maximurn contact load decreases first and then increases. The clearance values in the range of -0.2 mm-0 mm have life effect on the static load-carrying capacity of bearing. With the increase in the curvature radius coefficient of raceway groove and the decrease in the initial contact angle, the static load capacity of bearing decreases.     

18Ni钢表面软化技术研究

18Ni是马氏体时效型超高强度钢,广泛用于航空和航天。该钢经固溶时效处理后,具有极高的强度和韧性。在某些工程应用中,要求18Ni材料加工的零件基体具有较高的强度和硬度,以获得必需的结构强度,同时要求表面具有较低的硬度。本文通过采用激光热处理的方法,在模拟某吊挂零件的18Ni材料试样表面获得了深度0．2～0．5mm、硬度HV282～320的表面软化层,达到零件使用设计指标,使该钢种作为某型发射架吊挂零件的工程应用成为可能。