平面四杆机构曲线动态数值图谱的简易实现

用几何直接求解四杆机构的主要运动参数 ,结合位置解法求解连杆上点的坐标值 ,用Math CAD软件实现连杆曲线的动态数值图谱。并把该方法用于四杆机构性能分析 ,以便于结合图谱法与数值法的优势进行连杆机构的设计     

平面四杆机构曲线动态数值图谱的简易实现

用几何直接求解四杆机构的主要运动参数，结合位置解决求解连杆上点的坐标值，用MathCAD软件实现连杆曲线的动态数值图谱。并把该方法用于四杆机构性能分析，以便于结合图谱法与数值法的优势进行连杆机构的设计。     

变杆长参数化四杆机构的运动学仿真

基于商用软件平台ADAMS,采用参数驱动技术创建了铰链四杆机构的运动学仿真模型和相应的人机操作界面,通过建模和运动学仿真,方便快捷地绘制了精确的四连杆机构分析图谱,实现了铰链四杆机构连杆曲线图谱的绘制功能,从而为四杆机构设计提供了准确的设计数据.该研究成果对于四杆机构运动轨迹选型和尺度综合具有一定的工程指导意义和应用价...     

小曲柄齿轮五杆轨迹同源机构的尺度综合研究

讨论了小曲柄齿轮五杆机构的尺寸约束条件,根据复矢量理论和Fourier级数理论,分析了小曲柄齿轮五杆机构连杆轨迹谐波特征参数的特性,为数值图谱库中数据的压缩奠定了理论基础,建立了较为完善的小曲柄齿轮五杆机构连杆转角算子谐波特征参数的数值图谱,并对双曲柄齿轮五杆轨迹同源机构的几何关系进行了分析,实现了利用数值图谱法进行小曲柄齿轮五杆轨迹同源机构的尺度综合.综合算例表明该方法实用方便.     

利用数值图谱法进行齿轮四杆刚体导引机构的尺度综合

讨论了带有预定时标齿轮四杆机构的刚体导引位置函数与连架杆摆角函数之间的关系，并对连架杆摆角函数曲线的平移进行了分析，建立了包含34545组机构基本尺寸型连架杆摆角函数谐波成分的数值图谱库，实现了利用数值图谱法进行齿轮四杆刚体导引机构的尺度综合方法，最后给出了综合算例。     

N杆Assur杆组构型综合图谱库研究

简要论述了杆组型综合研究现状,分析并归纳了杆组结构特征参数表达式,基于此提出杆组的特征值;并提出一种新的杆组拓扑图绘制原则。针对不同的杆组特征值,基于杆组拓扑图绘制方法,使用排列组合可快速、准确地进行N杆组构型综合分析。列表给出了杆组环数小于2、10杆组以内的所有全铰链杆组的特征值、构型拓扑图、结构图图谱库,通过一个实例说明特征值和图谱库对于机构级别分析的鉴别意义。拓展了基于杆组的机构型综合理论研究,为基于杆组法的机构研究与应用提供了一个详实的、可供参考的杆组构型图谱库。     

平面四杆机构少位置设计要求特征提取方法

针对数值图谱法无法直接求解平面四杆机构少位置设计要求的轨迹综合问题,基于复函数最小二乘法,提出了一种利用傅里叶级数对少位置点近似逼近,实现少位置离散点特征提取的方法。发现了少位置点的平移、旋转、缩放后的特征参数与原始位置少位置点的特征参数之间的内在联系。结合数值图谱法,对平面四杆机构少位置设计要求轨迹综合问题进行求解。综合结果证明,所提出的方法对少位置设计要求的轨迹综合问题具有适用性和有效性。     

平面六杆机构电子图谱库的构建

六杆机构作为一种混合驱动机构,可以实现各种复杂的连杆曲线。针对目前实现期望轨迹优化六杆机构时初值难选,有时难于收敛,传统图谱查询效率低,过程烦琐,识别精度低等难题,基于数学形态学形状谱提取轨迹参数,构建了六杆机构的电子图谱库,实现了期望轨迹的准确快速查询,为实现期望轨迹的机构设计提供了技术手段。     

五杆双输入机构的输出特性图谱及输出特性分析

利用ＦＦＴ对常用的典型五杆双自由度机构，在其输入均为匀速转动的条件下，建立了其输出特性－输出函数和连杆上轨迹的特征参数图谱，并对其输出特性与五杆机构的尺度、输入角速度、输入转角的初始值之间的关系进行了分析，得到一些规律性的结论，有助于利用五杆机构的输出特性图谱进行五杆机构的尺度综合，并为多杆机构的特性研究提供了帮助．     

利用数值图谱法进行多杆直线导向机构的轨迹综合

给出了类四杆五杆机构的几何约束条件,讨论了类四杆五杆机构连杆轨迹与连杆转角算子之间的关系,建立了包含137052组机构基本尺寸型的特征参数数值图谱库,实现了对带有预定时标多杆直线导向机构的轨迹综合,文中最后给出了算例对其进行验证。     

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.     

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.