电液伺服阀动态特性数据处理方法的研究

电液伺服阀动态测试过程中,由动态缸高频振动引起的测试台架振动、现场存在变频器等设备造成的电磁干扰以及传感器电源波动等因素,均会以速度测试通道噪声的形式窜入数据采样通道,这些噪声信号幅值强弱不同且频宽很广,采用硬件滤波手段难以有效消除,导致电液伺服阀的频率特性测量数据信噪比降低,如果不进行有效的数据滤波处理,会导致对电液伺服阀动态性能评价失效。针对这一问题,提出了采用FIR和IIR滤波器双联滤波的方法,并对含有上述噪声信号的数据进行了理论分析和实验研究,结果表明,该方法有效的消除了非线性干扰,提高了电液伺服阀动态特性的测量精度。     

电液伺服阀动态性能测试技术的研究

电液伺服阀动态性能测试是其性能测试的难点，文章介绍了采用计算机完成伺服阀动态性能测试的技术，并研制出一套实用性强、可靠性高的计算机辅助测试装置，可测最大流量为40L/min电液伺服阀的动态性能，经实际测试和对比试验验证了该测试系统的合理性和准确性。     

电液伺服阀测试系统研究

该电液伺服阀测试系统主要用来测试伺服阀的静态和动态性能。介绍了系统纽成及功能，研究了系统的测试原理图，最后分析了伺服阀的静态和动态测试。     

电液伺服阀静动态性能测试系统的研制

电液伺服阀静动态性能测试系统是一套高度自动化的计算机辅助测试系统，文章介绍了伺服阀的测试方法，并研制出一套完全由计算机完成、可测流量为40L／min的电液伺服阀静动态性能的试验装置，经实际测试和对比试验验证了本测试系统的合理性和可靠性。     

基于LabVIEW的流量控制阀测试系统的研究与实现

设计了基于LabVIEW的电液伺服流量阀和电液比例流量阀静动态特性的自动测试系统,在分析测试对象的基础上,重点研究了测试系统的硬件架构以及软件实现方案。     

电液压力伺服阀测试系统设计

应用现代计算机辅助测试系统理论和技术，对国产某型飞机电子防滑刹车系统中的电液压力伺服阀（FF105）的离线性能综合测试系统进行了设计与研究。     

电液伺服阀的研究现状和发展趋势

文章从结构改进、测量和测试设备技术、动态性能研究、故障检测技术和新型阀的研制等方面介绍了电液伺服阀的研究现状。对电液伺服阀的发展趋势进行了展望。     

基于虚拟仪器的电液伺服阀静动态特性测试

介绍了采用虚拟仪器实现对电液伺服阀进行静动态特性测试的方法以及虚拟仪器技术和本测试系统的软硬件组成。事实证明,采用了利用虚拟仪器的计算机辅助测试（CAT）系统,使电液伺服阀的测试实现了自动化,简化了仪器仪表等设备,加快了测试速度,提高了测试精度。     

电液伺服阀计算机辅助测试系统研制

介绍电液伺服阀计算机辅助测试系统的功能、组成及工作原理。该系统能自动完成伺服阀静动态特性测试并同步实现计算机化数据处理,通过实际测试和对比试验验证,使用效果良好。     

2D数字伺服阀的简介

该文主要阐述了2D数字伺服阀的结构原理及工作原理,建立了电—机械转换器的数学模型,设计了2D数字伺服阀控制器。为了获得电—机械转换器及样阀的性能,对其进行了实验研究,实验结果表明,该电—机械转换器具有良好的频率特性,对应-3dB、-90°的频宽约为250Hz;2D数字伺服阀具有良好的静态、动态性能,其分辨率与滞环皆在1%以内,阀在25%满量程正弦输入信号下,对应-3dB、-90°的频宽约为130Hz。     

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.