保持架铆钉孔位置度测量方法

针对深沟球轴承分离型半保持架铆钉孔孔径较小,三坐标测量机测头在孔中移动距离受限,无法测量孔位置度的问题,利用三维光学测量仪,采用1/2最大极角偏差修正方法,在极坐标系实现了小孔径孔位置度的测量,并通过实例验证了该方法的可行性。     

CMM测量中复杂零件的路径规划研究

在复杂零件的三坐标测量路径规划中,测量点的排序存在组合优化问题。以测头角度变换次数最少为原则,采用对待测几何特征按测头角度的可达性进行分组,并对其进行集中测量的方法,基于多色集合理论建立了问题的约束模型。根据此约束模型,利用遗传算法对路径规划中的几何特征测量排序进行优化。针对实例零件,验证了复杂零件的全局路径规划问题。     

用空气静压轴承定位测量同轴度

带有台阶孔的机械零件,其孔间同轴度误差的大小,对该零件或使用该零件的成品功能是至关重要的。 如图1所示零件,两台阶孔间同轴度要求较高,这种误差若采用机械量具进行测量,不仅费时费事,且由于受机械量具精度和定位件精度的限制,测量误差就大。如采用三坐标测量机或圆度仪测量,保证了精度,但成本太高,效率很低。现采用空气静压轴承定位的组合测量,既能保证测量精度,又能降低成本,提高效率。现介绍如下:     

一种锥孔锥角误差比较测量仪新结构

本文介绍了一种采用标准锥孔样件作比较，测量出锥孔锥角误差的新比较测量仪；利用此仪器原理设计出的角度测量仪，可以满足锥孔零件加工在线停机或离线的角度误差定量检测，保证了锥孔加工过程中的测量控制。     

箱体类零件空间尺寸的测量方法

在生产加工中,许多零件的尺寸都是由空间尺寸构成,尤其是箱体类零件。箱体类零件通常涉及平行孔系、垂直孔系和相交孔系,这就使孔系与孔系、孔与孔之间构成了大量的空间尺寸。常规的测量工具无法实现空间尺寸的测量,需借助三坐标测量仪等精密测量仪器对工件空间尺寸进行检测。在未借助三坐标测量仪的情况下,通过自制专用检具,运用数学几何方法,将空间尺寸转换为平面尺寸,实现了对箱体类零件空间尺寸的测量。     

泵类产品托架半孔同轴度检测方法

正目前,在机械制造行业中,对于半孔零件的同轴度检测,通常采用以下3种检测方法。(1)采用镗床检测。在镗刀杆上装上磁力百分表,通过镗刀杆带动百分表旋转,测量孔的同轴度。这种方法的不足:一是占用机床,造成机床资源浪费;二是费时费力,效率低下,适合单件生产,而不适合多件或批量生产。(2)采用三坐标测量仪检测。这种方法是用探头在基准孔上打点,并将打出的点拟合成圆柱,以该圆柱的最佳中心线作为测量基准线,然后用同样方法得到被测孔的中心线,通过判断被测孔中心线与基准中心线的偏差,计算出同轴度误差。在此测     

扭簧比较仪测量力的检测方法

介绍了用架盘天平和砝码等量具组合精准检测扭簧比较仪测量力的方法,该方法也可以被用来检测机械式比较仪及类似结构量具的测量力。通过确定该类测量仪表的测量力,可以减少薄壁零件的测量变形量,提高产品质量。     

三坐标测量仪在复杂零件检测中的应用

探讨盖板零件精度检测问题,采用三坐标测量仪进行自动化检测的方法。通过实验结果可以得出,三坐标测量仪是一种高效、准确、可靠的检测手段,具有高精度、高效率、多功能和适用性广等优点。首先,三坐标测量仪能够快速、准确地获取零件的各项数据,从而大大提高了检测效率。它具有较高的精度和重复性,能够满足对高精度零件的检测要求。此外,三坐标测量仪还具有灵活性强、适应性广等特点,适用于不同类型、不同形状的零件。采用三坐标测量仪进行精度评估是一种方便、准确的方法,特别适用于复杂零件的自动检测。三坐标测量仪还具备数据分析和统计功能,可以更好地了解零件的质量状况以及生产过程中存在的问题。然而,三坐标测量仪也存在一些局限性。由于其复杂的结构和高精度的要求,造价较高,不是所有企业都能够负担得起。其次对于大型零件或特殊形状的零件,三坐标测量仪的测量范围可能受到限制。操作三坐标测量仪需要一定的专业知识和技能,对操作人员的要求也较高。因此,三坐标测量仪是一种高效、准确、可靠的检测手段,值得在各个领域广泛应用。     

基于人工免疫算法的三坐标测量机路径规划

为了提高三坐标测量机(CMM)的测量效率,提出多色集合理论模型与人工免疫算法相结合的方式规划CMM自动测量路径。通过待测特征与测头特征、测头角度和待测面的关系建立多色集合围道矩阵,然后进行合取运算建立合取围道矩阵;结合多色集合理论约束模型,采用人工免疫算法,优化全局测量路径。实例表明,该算法提高了三坐标测量机自动检测效率,并已用于实际检测,具有一定实践意义。     

规则约束和蚁群算法三坐标测量路径规划研究

为了提高三坐标测量中测量路径的有效性和合理性,采用带有规则约束的蚁群算法对三坐标测量路径进行优化。基于新一代GPS相关思想,将"几何要素"作为规划对象,并结合实际测量规则及相关理论研究,提出了测头路径规划规则。利用多色集合中的围道布尔矩阵建立了被测几何要素与测头角度和检测平面之间关联关系的形式化描述模型,在该模型与相应规划规则的共同约束下,利用蚁群算法对路径进行优化。经实例验证,表明该方法可靠、有效。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.     

Fractional order nonsingular terminal sliding mode control for flexible spacecraft attitude tracking

This paper investigates a fractional terminal sliding mode control for flexible spacecraft attitude tracking in the presence of inertia uncertainties and extern...     

奥氏体不锈钢表面双辉等离子渗锆的动力学

利用双辉等离子渗金属技术在0Cr18Ni9Ti奥氏体不锈钢表面制备了一层均匀、致密、呈良好冶金结合的渗锆合金层,并对1 060℃下的渗锆动力学进行了研究。结果表明:随着距锆合金层表面距离的增加,锆元素的含量呈梯度递减,扩散系数逐渐减小,而扩散激活能逐步增大;在1 060℃采用双辉等离子技术渗锆时,渗锆合金层表层的空位密度为2.945×(1012~1013)cm-2,与相同温度下采用常规渗金属工艺相比,提高了1~2个数量级。     

气化炉三维扫描测量与数据处理

以德士古气化炉耐火砖的内壁蚀损检测设备为基础,对采集到的点云数据做了进一步处理.通过对数据的筛选和剔除,实现了数据点的平滑降噪细化和精简.然后利用点云对整、网格划分和分色显示等方法,最终完成了内壁腐蚀情况的三维建模.重点讨论了点云数据的预处理及后处理的方法,并根据内壁耐火砖的腐蚀阈值,提出了一种气化炉内壁腐蚀区域的识别与分割方法.对耐火砖的腐蚀分析、气化炉的生产与维修提供了可靠依据,并在工程应用中获得了一致认可.