航空叶片的三坐标自动测量技术

针对航空叶片三坐标自动测量技术研究现状,基于CAD数模的自动测量方法、自动定位夹具设计参考规则及先进自动测量系统特点三方面展开论述,并总结了航空叶片自动测量技术的未来发展趋势。结合检测效率低等问题,对比了4种解决方案,通过改进叶型检测流程,设计了一种燕尾型榫根叶片的自动测量夹具。     

汽轮机叶片三坐标测量的自动定位研究

使用三坐标测量机对汽轮机叶片进行检测时多数是以单件测量的方式进行,每次测量都需手动建立坐标系,增加了人机交互的环节,测量效率低下。设计开发了叶片测量专用夹具,通过实验验证,符合三坐标测量机的测量精度,为实现汽轮机叶片计算机集成测量自动化提供了解决方案。     

压气机叶片榫头轮廓数字化检测技术研究

基于三坐标测量机PC-DMIS软件测量系统和叶片UG模型,通过编制自动测量程序对叶片榫根的检测方法进行了研究,解决了使用传统投影法对榫根变公差轮廓度尺寸检测不精确和无法量化的问题和跨棒距数字化计算问题,同时采用自动化检测、批量矩阵式检测方式提高三坐标测量机在叶片检测中的效率。     

叶片型面CMM测量规划与仿真系统研究

为优化三坐标测量机对叶片型面的检测过程,针对叶片测量特点研发了一种虚拟仿真检测系统.该仿真系统以叶片为研究对象,通过建立三坐标测量机和叶片的三维实体模型对叶片测量路径进行规划,提取叶片测头中心点坐标,并根据矢量平均误差确定测头矢量的优化算法进行测头半径补偿,完成叶片测量点曲面与理论模型的误差比对及测量过程仿真.     

高效的航空发动机叶片余量分析方法研究

航空发动机是飞机的关键动力部件,关乎一架飞机的飞行性能和安全性。由于叶片的空间复杂性,可借助高精度的三坐标测量机获取可靠的叶片型线测量报告。然而,叶片型线测量报告的数据离散且不够直观,这给一线的加工和返修带来不便。提出一种叶片加工余量分析系统并开发了叶片余量分析软件,该系统可以读取三坐标测量机生成的.res格式的叶片型线测量报告,首先按行读取叶片型线测量报告;然后使用二叉排序树将叶片点云按照偏差值进行排序;最后,叶片加工余量分析系统对叶片点云进行余量分析并给出统计报告,支持叶片点云和CAD数模的可视化和Excel报告的导出。该系统有利于提高叶片加工的效率。     

CORE-M光学高速测量机

如果将透平叶片放在三坐标测量机上检测会出现什么问题？测量效率低,叶片前后缘测量效果不佳,扭曲叶片还会产生测针半径补偿误差。如果运用一般3D光学扫描来测量叶片,对高反光表面叶片需要喷涂显影剂,这样则会造成测量结果失真,因而不能正确显示被测零件的实际情况,且设备本身精度也不高。     

三坐标测量机测量过程与误差探析

三坐标测量机是一种现代化自动检测设备,被广泛应用于机械、航空、军工、教育等行业,具有高精度、高效率、高稳定性等特点。其测量过程有严格的要求与规程,合理的测量方案流程设计能在一定程度上提高测量精度与效率。本研究对三坐标测量机测量过程的主要环节进行分析与讨论,如测量环境要求、测头校验、建立工件坐标系、工件位置摆放及采点个数与位置,另外,分析讨论了测量过程中产生的误差来源,主要包括方法误差、设备误差、人员误差、环境误差,并提出应对策略。实践证明,严格、合理的测量流程与误差分析是实现三坐标测量机高精度、高效率测量的重要保障。     

YP02型叶片测量仪控制系统的研制

针对自行研制的YP02型叶片测量仪，介绍了其控制系统的硬件和软件结构及测量过程。该测量仪具有较高的测量效率及自动化程度，可用于叶片加工工序间的测量及成品测量。     

三坐标测量机在零件自动检测中的应用

通过具体的检测实验,介绍了三坐标测量机在批量零件的自动检测中的应用.实验结果证明:采用三坐标测量机对批量零件进行测量,大大提高测量精度和测量效率,具有较好的实用性.     

三坐标机探针测头的选用

三坐标测量机作为高端精密测量仪器之一,选择合适的探针测头,可以有效的提高测量精度和测量效率。本文首先采用正交试验,从探头的半径与长度、探头的旋转角度、探头的接近距离、物体的大小四个方面分析,确定探头的半径与长度对精度影响比较大。其次采用半径筛选法,以叶片背弧面为例,确定最佳测头半径。该方法已用于叶片测量中,改变了以往传统多次试测选择测头的方式,提高了测量的准确性和测量效率。     

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.