主减速器总成质量评判方法的研究

根据汽车主减速器的结构和传动性能检测要求,分析了主减速器在运行过程中产生的各种噪声及其原因,依据噪声辐射与振动的关系,分析该振动信号所携带主减速器运行的各种信息.使用工控机在线对主减速器壳振动信号进行采集,提出一种以LabVIEW技术为基础,采用时域和频域两种分析方法对信号进行处理,通过提取混合特征识别主减速器故障的方法.实验表明了该方法的有效性.     

基于Gabor变换的轮边减速器特征提取技术

研究矿用自卸车轮边减速器中部件局部故障振动信号的频谱结构,对于轮边减速器故障诊断具有重要意义.模拟内齿圈局部故障振动信号,利用Gabor变换提取方法对含噪声的故障振动信号进行降噪,并应用频谱分析方法诊断出了内齿圈故障,显示了该方法在信号提取和压制噪声的效果,为矿用自卸车轮边减速器故障诊断提供了有效的诊断方法.     

小波分析-模糊聚类法在滚动轴承故障诊断

为了对减速器内轴承的运行状态进行故障监测和诊断,在对振动加速度信号进行小波分析的基础上,提出了基于尺度-能量谱的特征提取和模糊聚类相结合的滚动轴承故障诊断方法.该方法应用于齿轮减速器JZQ250的故障诊断中, 经对大量实测数据的处理和分析,能够比较准确地识别和诊断出减速器的正常运行状态、内圈故障和外圈故障运行状态,具有一定的工程实用价值.     

基于小波包分析的桥式起重机减速器齿轮故障诊断

齿轮故障是影响减速器正常运行的关键问题。采用声发射检测手段,针对减速器齿轮中正常、齿根裂纹、齿面磨损及断齿四种状态进行分析,提取减速器齿轮工作过程中的声发射信号进行诊断。采用基于最小模糊隶属度的信息融合方法诊断减速器齿轮故障。实验结果表明,诊断结果的准确率较高,表明此方法可实现对减速器齿轮故障状态的实时精确诊断,研究结果为及时发现和更换失效齿轮,对提高减速器的工作效率和使用寿命等方面具有重要意义。     

一种起重机减速器故障诊断试验台及测试方法

为了研究起重机减速器故障与其振动特征信息的关系,通过检测减速器振动信息来判断减速器故障的类型、位置及程度,设计了一种减速器故障诊断试验台,包括试验台本体、起升机构、测试分析系统等,并据此制作了样机,同时提出了一种减速器故障的测试分析方法.测试结果表明,基于该试验台及测试方法,采用变时基谱、离散傅里叶变化等分析方法能够准确获取减速器振动特征信息,对减速器做出的故障诊断与实际开箱检查测量的结果一致.根据建立的振动特征信息库,可对使用现场的减速器进行检测及故障判定.相比通常需打开减速器才能对其进行故障判别的方法,这种方法无需打开减速器即可对其进行方便、快捷、准确地检测及故障诊断,对保障起重机安全运行具有重要意义.     

一种起重机减速器故障诊断试验台及测试方法

为了研究起重机减速器故障与其振动特征信息的关系,通过检测减速器振动信息来判断减速器故障的类型、位置及程度,设计了一种减速器故障诊断试验台,包括试验台本体、起升机构、测试分析系统等,并据此制作了样机,同时提出了一种减速器故障的测试分析方法.测试结果表明,基于该试验台及测试方法,采用变时基谱、离散傅里叶变化等分析方法能够准确获取减速器振动特征信息,对减速器做出的故障诊断与实际开箱检查测量的结果一致.根据建立的振动特征信息库,可对使用现场的减速器进行检测及故障判定.相比通常需打开减速器才能对其进行故障判别的方法,这种方法无需打开减速器即可对其进行方便、快捷、准确地检测及故障诊断,对保障起重机安全运行具有重要意义.     

小波分析-模糊聚类法用于滚动轴承故障诊断

为了对减速器内轴承的运行状态进行故障监测和诊断,在对振动加速度信号进行小波分析的基础上,提出了基于尺度-能量谱的特征提取和模糊聚类相结合的滚动轴取故障诊断方法。该方法应用于齿轮减速器JZQ250的故障诊断中,经对大量实测数据的处理和分析,能够比较准确地识别和诊断出减速器的正常运行状态、内圈故障和外圈故障运行状态,具有一定的工程实用价值。     

基于MCSA和Fisher-SAE的RV减速器故障特征提取研究

针对RV减速器实际监测中振动传感器的安装空间和信号采集容易受到限制和干扰等问题,提出了一种基于电机电流信号分析,稀疏自编码和Fisher准则相结合的RV减速器故障特征提取方法。首先,将采集的驱动电机电流数据转换到频域,研究了不同超参数对稀疏自编码的特征提取能力的影响,利用优化参数后的稀疏自编码对频域信号自动提取故障特征;然后,利用Fisher准则对提取的特征的判别能力进行了降序排名,取排名前n个特征,得到了最优故障特征集;最后,结合SoftMax分类层,实现了对RV减速器的故障诊断;搭建了RV减速器故障实验台,采集了电机电流数据,对基于Fisher-SAE的方法进行了验证,并将其与其他典型机器学习故障诊断方法进行了对比。研究结果表明：该方法能够从RV减速器电机电流信号中提取出故障特征,并选择最有效的故障特征集,解决了振动信号的局限性以及运用电流信号进行故障诊断难以提取有效特征的问题;相比于其他典型机器学习故障诊断方法,该方法的诊断准确率提高了10%～20%,具有更好的诊断效率和准确性。     

矿用带式输送机减速器输入轴断裂分析及措施

为降低矿井带式输送机的减速器高速轴断裂故障率,通过对减速器伸出轴渗漏油原因分析,提出了优化减速器通气罩伸出轴密封结构设计及措施,实践运行验证效果良好,改善了伸出轴渗漏油情况,保障带式输送机减速器的稳定运行,达到延长减速器使用寿命、降低设备故障率。     

一种准双曲面齿轮主减速器的故障诊断方法及实现

介绍了一种采用主减速器总成跑合试验的振动信号进行准双曲面齿轮主减速器质量评价的方法。利用时、频域分析和小波包分解对能反映故障特征的参数进行提取;利用MATLAB神经网络工具箱对BP神经网络进行训练并实现故障模式的识别。通过实测信号的试验结果表明,该方法能对准双曲面齿轮主减速器的质量进行有效的评价。     

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.