大数据下机械装备故障的深度迁移诊断方法

机械故障智能诊断是大数据驱动下保障装备安全运行的重要手段。为准确识别装备的健康状态,智能诊断需要依靠充足的可用监测数据训练智能诊断模型。而在工程实际中,机械装备的可用数据稀缺,导致训练的智能诊断模型对装备健康状态的识别精度低,制约了机械故障智能诊断的工程应用。鉴于实验室环境中获取的装备可用数据充足,即数据的典型故障信息丰富、健康标记信息充足,且此类数据与工程实际装备的监测数据间存在相关的故障信息,提出机械装备故障的深度迁移诊断方法,将实验室环境中积累的故障诊断知识迁移应用于工程实际装备。首先构建领域共享的深度残差网络,从源自不同机械装备的监测数据中提取迁移故障特征;然后在深度残差网络的训练过程中施加领域适配正则项约束,形成深度迁移诊断模型。通过实验室滚动轴承与机车轴承的迁移诊断试验对提出方法进行验证,试验结果表明:提出方法能够运用实验室滚动轴承的故障诊断知识,识别出机车轴承的健康状态。     

深度卷积长短期记忆网络的轴承故障诊断

针对传统数据驱动故障诊断方法难以从轴承信号中自适应提取有效特征、没有充分利用故障数据的时序特点以及缺乏自适应处理动态信息能力的问题,提出了一种深度卷积神经网络与长短期记忆网络相结合的智能故障诊断方法.本文方法构建的深度模型能够从轴承原始信号中自适应地提取鲁棒性特征,然后利用长短期记忆网络学习特征中的时间依赖关系实现了高准确度的轴承故障诊断.该方法克服了传统特征提取方法依赖专家经验和信息利用不完全等问题,实现了故障的智能、准确诊断.实验结果表明,该方法可以提取更准确的特征而且由于利用了故障演变过程中的时序信息,使得故障诊断更加智能、可靠.     

基于FFT-SDAE的地铁牵引电机轴承故障智能诊断

针对地铁牵引电机轴承故障诊断中因工况复杂影响人工提取特征效果的问题,提出了一种基于快速傅里叶变换(Fast Fourier Transform,FFT)和堆叠降噪自编码器(Stacked Denoising Auto Encoder,SDAE) (FFT-SDAE)的地铁牵引电机轴承故障智能诊断方法.首先,使用大量无标签数据预训练深度自编码器的特征提取能力,自适应提取轴承故障特征;然后,通过小样本有标签数据微调网络学习分类性能,搭建地铁牵引电机轴承的FFT-SDAE网络模型;最后,通过试验研究FFT-SDAE网络结构对轴承故障诊断准确率的影响,选取最佳网络参数.试验结果表明,在变转速和变载荷的情况下,所提方法可以很好地提取故障的深层特征,在使用工况较复杂的数据集时,所提方法的诊断准确率优于传统的故障诊断方法.     

QDY型桥式起重机安全故障智能诊断方法

针对采用现有故障诊断方法诊断QDY型桥式起重机故障时，存在诊断结果与实际相差较大，且无法将全部故障问题查出的问题，开展安全故障智能诊断方法的研究。在QDY型桥式起重机运行中，获取起重机运行数据，并完成对数据的归一化处理。再基于起重机故障的多种类型，建立起重机安全故障模型。基于贝叶斯理论，通过计算起重机故障先验概率、条件概率等参数，实现对起重机故障的智能诊断。将新的故障诊断方法应用于实际，可实现对起重机多种故障类型的准确诊断，且能够全部找出同一时刻多种故障类型，具备极高的应用价值。     

基于模糊支持矢量数据描述的早期故障智能监测诊断

为了解决机电设备早期故障难以正确识别及故障发展状态不易准确监测的问题,提出了一种基于模糊支持矢量数据描述(FSVDD)的早期故障智能监测诊断新方法。该方法只需要一类目标样本作为学习样本就可以建立起单值分类器,同时在核函数中引入非目标样本的模糊隶属度,从而把非目标样本与目标样本分等级地区分开来。将这种方法应用在机电设备状态监测和故障诊断中,只需要将正常运行时的数据信号作为目标样本,就可以实现对设备早期故障的准确识别,同时判断故障的严重程度。在轴承运行状态监测中的测试结果表明,该方法不仅能快速识别轴承的早期故障,而且可以对故障的严重程度做出准确的判断。     

基于层次分析-云模型的大型LNG高压泵自停故障智能诊断方法

为诊断大型LNG高压泵自停状态是正常保护动作，还是高压泵自身故障所致，提出基于层次分析-云模型的大型LNG高压泵自停故障智能诊断方法。采用层次分析-云模型的高压泵运行状态识别方法，由层次分析模型构建高压泵运行状态评价指标体系后，由云模型的正向云发生器，分析高压泵运行状态的评价指标隶属度，识别处于自停状态的高压泵；使用基于卷积神经网络的自停故障智能诊断方法，由小波包方法提取自停高压泵的振动信号特征后，输入卷积神经网络，实现自停故障诊断。实验结果显示：此方法对大型LNG接收站中6个高压泵自停状态识别后，自停的6号高压泵属于3级故障，为非正常保护动作，诊断结果准确。     

基于EEMD-SVM的自动扶梯主驱动轴轴承故障诊断方法研究

针对自动扶梯由于长期处于高员载运行状态而引起主驱动轴轴承故障问题,提出一种基于EEMD-SVM的自动扶梯主驱动轴轴承故障诊断方法。使用集合经验模态分解(EEMD)对轴承异常的振动加速度信号进行分解来提取信号特征,然后基于支持向量机(SVM)构建故障诊断模型对信号进行诊断,从而确定故障状态。     

变工况下基于信息融合的地铁牵引电机轴承故障智能诊断

针对传统滚动轴承故障诊断方法过于依赖先验知识和专家经验,以及单一信号对某些故障识别率偏低的问题,提出一种变工况下基于信息融合的地铁牵引电机轴承故障诊断方法.首先搭建滚动轴承试验与多信息采集系统;其次对地铁牵引电机轴承进行缺陷预制并采集轴承试验过程中的声发射和振动信号;然后用小波包分解对原始信号进行处理并提取特征,再用卷积神经网络对归一化后的特征信息进行融合;最后建立二维卷积神经网络模型,对不同工况下的地铁牵引电机轴承故障进行智能诊断.试验结果表明:变工况下基于信息融合的地铁牵引电机轴承故障智能诊断方法,可在载荷和转速变化的情况下准确识别轴承的故障类型,当神经网络训练集与测试集涵盖工况相同时,准确度可达100％.     

齿轮裂纹特征提取和故障诊断方法研究

齿轮作为旋转机械中的关键部件,其健康状态是判断设备能否继续运行的重要指标,因此,准确快速的对齿轮早期故障进行诊断极其重要。提出了一种基于欧氏距离技术(EDT)的齿轮故障诊断新方法,该方法选择提取振动信号的频带能量作为特征参数,然后计算测试样本和各不同健康状态下频带能量组成的矩阵之间的欧氏距离,距离最小者为测试样本所属状态类别。采用实验数据验证该方法的准确性,结果表明,EDT方法能有效的诊断齿轮早期裂纹故障且与同类方法相比具有更高的准确性;同时,分析对比结果可知,频带能量在齿轮裂纹故障诊断中是一个比较敏感的特征参数,可以考虑为后续使用。     

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...     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

Fifth International Summer School on Screw-Theory Based Methods in Robotics

正3-11 September,2014University of Bologna,Bologna,Italy www.summerscrews.org summerscrews2014.ing.unibo.it SUMMER 20SCREWS 14In 2014,our screw-theory school comes to the world's oldest university.In early September,Summer Screws'14 will gather six experts in the application of screw theory in robotics and up to 40 participants at the University of Bologna,Bologna,Italy.The school will teach attendees how to apply existing methods and empower them to develop new ones in their own research.The basic theoretical notions will be introduced in a rigorous manner,emphasizing examples,applications,and exercises.Scholarships are available.     

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.     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

INDUSTRIAL ENGINEERING AND VISUALISATION-A PRODUCT DEVELOPMENT PERSPECTIVE

Taking the actual project of teaching and researching process for example, the relationship between the industrial engineering and product development is discussed. And use the novel visualization technology to support the industrial engineering and product development. How to use the new computer modeling and simulating technologies to support the product development and industrial engineering, is introduced especially. The support includes both domestic products and industrial systems. The visualization and computer technologies take a very important role in some system or multi-direction modeling, those technologies mentioned above can help the industrial engineers study the effect of design on the whole life circle, including the producing steps. So the engineers can avoid making the wrong decision which may cause bad effects on the whole industrial engineering.     

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.