深孔直线度检测装置的设计及应用

提出用臂杆法测量深孔直线度.设计出深孔直线度检测装置的结构,并进行了系统误差分析.经实测深孔油缸直线度,测量数据表明该深孔直线度测量系统能满足测量要求,对深孔零件直线度现场检测具有一定的实际意义.     

基于枪钻的超深孔直线度误差分析与试验研究

由于深孔加工朝着长径比、高直线度等方面发展,所以对深孔直线度误差作进一步研究有一定的现实意义。从枪钻加工过程中的初始偏移量、导向套与枪钻间隙值、枪钻系统偏心三个方面,对枪钻深孔加工直线度误差产生的机理进行分析研究,并结合理论分析,提出了降低和控制深孔直线度误差的方法。通过对某批超深孔工件的试验,验证了所设计组合式导向套在改善深孔直线度误差方面的作用,并通过对导向条进行合适的刃磨,可缩小直线度误差的波动范围。     

深孔直线度检测装置的设计及应用

提出用臂杆法测量深孔直线度。设计出深孔直线度检测装置的结构,并进行了系统误差分析。经实测深孔油缸直线度,表明该深孔直线度测量系统能满足测量要求,对深孔工件直线度现场检测具有一定的实际意义。     

深孔直线度检测系统设计与测算

深孔直线度的准确检测是深孔加工行业亟待解决的难题。为解决该难题,设计了一套深孔直线度检测系统,对不同深孔截面边界上多个点的坐标利用阻尼牛顿法求解深孔截面圆心,得出被测工件的实际轴线,最后通过"两端点连线法"计算出深孔直线度。为深孔直线度检测提供了一套检测系统与测算方案,该系统有利于提高测量精度与效率+;是深孔直线度检测的一个创新。     

切削液对深孔直线度的影响分析与应用

利用切削液流体Reynolds公式和其引起的钻杆弯曲变形、倾角方程,建立了深孔加工直线度误差方程,揭示了流体入口压力、钻杆转动、涡动、挤压与深孔直线度之间的关系。指出在切削稳定状态下,减小流体入口压力,增加钻杆转速、减小钻杆涡动速度或者减小钻杆挤压速度均可改善深孔直线度。设计了新型多级喷射装置,通过增设分流腔和喷射级数来降低入口压力,可有效减小深孔直线度误差。设计了挤压油膜阻尼器(squeeze film dampers,简称SFD),利用油膜阻尼力减小深孔钻杆的涡动与挤压运动,来提高深孔加工直线度。试验了多级喷射装置和SFD共同作用下的深孔直线度误差,验证了钻杆在较低流体入口压力、较小涡动和挤压作用下加工的深孔有更好的直线度,为控制深孔加工直线度误差给出新的思路及设计方案。     

深孔直线度检测系统

针对深孔直线度测量的实际问题,提出了基于PSD的位置检测技术,建立了以激光二极管、PSD和自动定心装置组成的检测系统。设计了系统的自动调节检测装置结构和光学部分,并对检测系统进行了分析。从而为深孔测量提供了一种检测技术,该系统能满足测量要求,对深孔直线度检测具有一定的前景。     

基于光轴法的深孔直线度测量装置设计

针对深孔直线度检测装置存在的环境适应性差、操作复杂以及直线度评定方法计算时间长等问题,提出了一种基于光轴法测量深孔直线度的方法,设计了以光电自准直仪为测量基础的深孔直线度测量装置。装置由反射镜、光电自准直仪、激光测距传感器组成的测量单元,与测量单元配合的高精度的自定心单元以及精密的行走单元组成。采用最小区域法与最小二乘法相结合的一种直线度评定算法更好地完成了深孔直线度测量,提高了深孔直线度测量的环境适应性,实现了深孔直线度的自动检测。     

挤压油膜阻尼器对深孔加工直线度的影响

深孔直线度误差是深孔钻削加工中的技术难题。为了提高深孔直线度和降低废品率,基于挤压油膜阻尼的工作原理设计了一种新型挤压油膜阻尼器,用于抑制深孔机床钻杆因转速过大造成的失稳。重点介绍了新型挤压油膜阻尼器的工作原理和系统动力学模型,并通过MATLAB仿真分析及试验验证,证实了新型挤压油膜阻尼器能够有效控制深孔的直线度误差。     

网格逐次逼近评定深孔轴线直线度误差的研究

针对深孔直线度误差评定中难以确定满足最小条件的评定基线的问题,提出利用网格逐次逼近评定深孔直线度误差的方案;以网格逐次逼近为寻优手段在两个半球面内搜索最优解,建立了满足最小条件原则的评定深孔轴线直线度误差的数学模型;将分别处于两个半球面内的节点两两组合放入坐标信息库的一行,每一行坐标信息确定一条评定基线,以一次网格细分后直线度误差值的最小值对应的两点重新构建球面逼近,通过球面的网格细分不断逼近最优解;网格逐次逼近评定深孔直线度误差可以为任意方向直线度误差的评定提供参考。     

基于相对比较测量法的深孔直线度测量系统

在分析国内外直线度测量方法和相对比较测量法原理的基础上,设计出了基于相对比较测量法的深孔直线度测量系统,对于解决深孔零件加工中的直线度检测具有实际意义。     

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...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

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。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

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.