基于分时复用反射电极结构的高精度绝对式时栅角位移传感器

提出了一种基于分时复用反射电极结构的高精度绝对式时栅角位移传感器。以增量式时栅传感器为基础,将单对极与多对极相结合,整周多对极作为精确测量部分实现高精度,整周单对极作为粗略测量部分实现绝对定位。提出了一种分时复用反射电极结构,粗测部分和精测部分共用一组反射电极和接收电极,因此结构更加紧凑,便于小型化,同时动子无需引线,应用环境更广。通过分时间段对粗测部分和精测部分施加激励信号,并把不工作的电极接地,可以有效消除粗测部分和精测部分之间的串扰,保证测量精度。采用PCB技术制造了外径Φ=60 mm,内径Φ=26 mm的传感器样机。通过理论分析和结构优化,最终实验结果表明传感器的测量精度达到了±12″。     

串并转换思想与绝对式时栅传感器的频响特性研究

在分析绝对式时栅位移传感器频响特性的基础上，介绍了一种在数字信号处理电路中的数据串并转换思想，并提出了一种基于串并转换思想的绝对式时栅信号处理电路设计方案。信号处理电路采用了复杂可编程逻辑器件（CPLD）芯片，预处理电路将测头信号进行模数转换后，经可编程多路切换器模块处理，自适应地将原始测头信号分别转换为对应的多路并行信号，各路对应的分频信号通过比相电路及传感器信号处理电路模块运算后转换为绝对位移脉冲测量信号，最后将多路绝对位移脉冲测量信号进行并串转换操作输出测量值。对信号处理电路进行了仿真，结果证明，该方法可大大提高时栅位移传感器的频响特性，从而为绝对式时栅位移传感器提供了一种应用于动态测控系统的解决方法。     

基于差极结构的绝对式直线时栅位移传感器研究及测量误差特性分析

针对传统绝对式位移传感器复杂编码和严苛光刻加工的难题,提出了一种"精机定位+精机测量"的差极结构绝对式时栅位移测量新方法.传感器定尺分为两列对极数相差1的激励绕组,每列激励绕组由空间正交排布的正/余弦绕组构成.通过施加正交激励电流,采用动尺正弦形感应绕组拾取时变磁场,得到两路行波信号.通过信号解耦以精机定位和精机测量的...     

小型化高精度绝对式时栅角位移传感器

针对机器人关节臂、关节臂式测量机等设备中所用绝对式角位移传感器面临的高精度和小体积之间的矛盾,研制了一种基于电场式时栅传感技术的绝对式、高精度、小型化角位移传感器。采用内圈单对极粗测结合外圈多对极精测的方式,实现绝对定位功能;采用单排差动传感结构能有效抑制共模干扰的优点,保证测量精度;采用传感电极和电路元件的集成化设计,实现了小型化。使用PCB工艺制作了外径为Φ=45 mm的传感器样机,通过实验分析表明,内外两圈之间的交叉串扰导致了对极内的一次谐波误差。在此基础上提出增大两圈间隙和布置中间屏蔽地的优化方案,使最终测量精度达到了±5.5″。该传感器在具备低功耗、低成本、小体积等特点的同时,拥有巨大的产品化潜力。     

基于斐波那契数列的双通道绝对式时栅设计

磁场式时栅角位移传感器的绝对式测量主要采用2个极对数呈互质关系的"精机+精机"的双通道组合形式实现。为了解决和优化传感器设计中两组极对数匹配问题,文中尝试引入斐波那契数列作为寻优化设计的参考,并为传感器设计提供参考。文中先后建立了传感模型,并通过有限元仿真软件开展了不同对极对数组合下的绝对式时栅的磁场仿真,仿真结果表明:各组仿真波形的感应行波信号的相位仿真值与理论值的误差可以保持在低于0.3°,且随着极对数的组合形式越趋近于黄金分割点,传感器仿真结果越好。因此,文中通过实验表明斐波那契数列可以作为绝对式时栅传感器结构设计的一种有利参考,对时栅传感器的寻优设计有一定的借鉴意义。     

寄生式时栅位移传感器测量原理与结构优化*

大型机床在实现全闭环数控过程中,现有测量方法存在回转工作台无法同轴安装角编码器、安装要求高、精度无法保证等方面问题,本文提出一种适用于大型、中空回转工作台角度测量的寄生式时栅位移传感器。传感器通过在两路空间正交的励磁线圈中通入两相时间正交的励磁信号,利用磁导调制方法得到相位差直接反映空间转角的电行波信号,从而实现精密角位移测量。建立由4个传感单元组成的传感器模型,采用电磁场有限元仿真软件建模并仿真,对仿真结果进行误差分析和溯源;根据分析结果对传感器进行结构优化并仿真验证;根据优化模型制作传感器实物,搭建试验台进行实验验证。实验结果表明,在整周范围内传感器测量精度达到±2″,实现了高精度测量,为寄生式时栅的进一步开发应用提供了理论依据。     

高精度绝对式差极角位移传感器

针对传统的大尺寸栅式角位移传感器在实现绝对定位的同时难以兼顾高精度测量的问题,在前期研究基础上设计了基于交变电场的大尺寸绝对式角位移传感器.传感器利用单列式传感结构实现高精度测量,设计内、外圈两圈结构在整周内刚好相差一对极以实现绝对定位.研制的传感器样机内径为100 mm、外径为154 mm,经实验测试并分析,其对极内...     

基于二次调制原理的多层结构绝对式角位移传感器

为了在传感器径向尺寸不变的前提下,保持良好的测量精度和分辨率,以适应小型化需要的工业场合,提出了一种利用多层结构实现信号二次调制的圆时栅角位移传感器。传感器为3层结构,利用轴向空间,使内外环分别通过多层结构完成信号的二次调制,其中内环作为粗测环经二次调制后用于实现传感器的绝对定位,外环作为精测环经二次调制后,提高了传感器分辨率。采用PCB工艺制造了外径Φ=100 mm,内径Φ=50 mm的传感器样机,初步实验表明内外环同时施加激励时,内外环将分别受到对方产生的串扰影响,因此进一步提出分时施加激励的优化方法避免信号串扰的影响以提升测量精度。最终实验结果表明传感器能够实现绝对定位且分辨率提升了1倍,原始测量精度达到了±4.1″。     

单相激励电容式时栅角位移传感器研究

针对现有多相激励时栅角位移传感器在小体积时无法设置更多极对数进一步提升稳定性,导致精度和动态性能指标无法得到提升等问题,提出一种单相激励电容式时栅角位移测量方法。该方法采用单相激励耦合成四路空间正交的驻波信号,通过电路实现行波构造,从而实现角位移测量。文中介绍了多相激励时栅传感器存在的问题、单相激励时栅的测量原理,完成了传感器样机的研制,并通过实验验证该原理的有效性。实验结果表明,相同尺寸和相同电极数量情况下,单相激励传感器的精度和动态性能指标优于多相激励传感器,单相激励传感器精度为±20″,稳定性为10″,400 rpm转速下速度波动为±1.25%,跟随误差为±2.5″,满足直驱电机的使用要求。     

基于光敏阵列直接调制的单栅式时栅位移传感器

针对传统叠栅形式光栅存在制造难度大、安装要求高等缺点,提出了一种用时间细分空间的单栅式时栅位移传感器。从光的粒子性出发,分析了用正交变化的光场信号合成光场电行波的方法;用点阵发光二极管(LED)模块作为交变光源,用空间正交的光敏阵列直接耦合光强信号获取了反应空间位移的电行波信号;最后,通过检测电行波信号与激励信号过零点之间的时间差,实现了对空间直线位移的测量。研制了原理样机,采用普通机械加工方法对其进行了实验验证。结果表明,在440mm测量范围内,样机的测量精度可达±2μm。该单栅式时栅位移传感器减少了叠栅式传感器对安装工艺的要求,提高了抗干扰能力;采用的测量技术避免了传统粗光栅技术存在的精度难以提高、动态特性差等缺点,为光学位移测量提供了一种不通过精密机械细分来提高测量精度的方法。     

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.     

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....     

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.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.