基于小波能量法的变速箱齿轮故障诊断技术研究

利用小波包分析并结合小波包能量谱尺度图的方法,通过小波包分解利用各频带范围信号能量的改变,进行了变速箱齿轮故障的诊断。按此方法准确地识别了某汽车H型变速箱的故障。研究表明,对变速箱齿轮故障诊断是一种行之有效的方法。     

基于小波分析的变速箱滚动轴承故障诊断方法的研究

利用小波分析技术将滚动轴承故障振动信号分解到时－频空间,定义了滚动轴承故障振动信号能量分布函数Ｓ（ｔ） ,提出了能量分布函数Ｓ（ｔ） 细化谱诊断变速箱滚动轴承故障的分析方法。在某自行火炮的变速箱上进行了一系列滚动轴承故障诊断实验,实验结果验证了能量分布函数Ｓ（ｔ） 细化谱诊断变速箱滚动轴承故障的有效性     

基于连续小波灰度图的变速箱故障诊断

为了诊断汽车变速箱的周期性冲击故障，利用连续小波变换灰度图分别对正常和故障汽车变速箱振动信号进行了分析。结果发现，连续小波灰度图不仅能识别变速箱的正常与故障，准确提取出周期性冲击故障信息，而且能够非常直观形象地表达出信号的细微结果，并进一步显示出故障变速箱中同时存在的两种相同频率的故障信息，从多层次、多方位观察到了分析信号的细微变化。     

基于小波变换-模糊聚类的变速箱齿轮故障诊断

在对车辆变速箱齿轮振动加速度信号进行小波变换的基础上，提出了基于尺度-能量谱的特征提取和模糊聚类相结合的车辆变速箱齿轮故障诊断方法。该方法应用于LC5T81变速箱齿轮的故障诊断中，能够比较准确地识别与诊断出变速箱齿轮的走合运行状态、磨损运行状态和故障运行状态，具有一定的实用价值。     

汽车自动变速箱的发展现状及其技术趋势

自动变速箱是现代汽车的关键总成之一。对液力自动变速箱、电控机械式自动变速箱、无级自动变速箱以及双离合器自动变速箱的发展现状进行了研究,分析了这四种自动变速箱目前存在的优势和劣势,并在此基础上对这四种类型自动变速箱的技术发展趋势进行了展望。液力自动变速箱将向多速化、轻量化、低噪声等方向发展,电控机械式自动变速箱将向高可靠性、协调化控制等方向发展,无级自动变速箱将向高扭矩传递能力、高传递效率等方向发展,双离合器自动变速箱将向高换挡性能、完善控制技术等方向发展。     

小波分析在车辆故障诊断中的应用

车辆变速箱振动信号可用小波分析法预处理后，再用小波包能量尺度图分析法识别故障，按此法对BJ212变速箱准确地进行了故障识别，结果表明利用小波分析进行变速箱故障诊断的方法行之有效。     

基于小波包近似熵和SVM的圆柱滚子轴承诊断

为了解决特种车辆变速箱圆柱滚子轴承由于振动信号的非线性、非平稳特征较为微弱,提取的特征量数值不明显且现实中难以获得大量含丰富特征的典型故障样本而难以对其进行准确诊断的问题,应用小波包近似熵和支持向量机对特种车辆变速箱圆柱滚子轴承进行诊断。首先,在自行搭建的模拟实验台上采集某型特种车辆变速箱圆柱滚子轴承正常、外圈磨损、滚动体故障、点蚀和压痕4种典型状态的振动信号;然后,分别提取4种典型状态振动信号的小波包近似熵值作为支持向量机的输入,根据支持向量机的输出结果来确定圆柱滚子轴承是否发生故障和故障类型。结果表明,该方法能有效对某型特种车辆变速箱圆柱滚子轴承的典型状态进行诊断,为其他相似变速箱圆柱滚子轴承的故障诊断提供一种参考途径,具有一定的工程实用价值。     

带式CVT带轮支承轴承

在变化的驱动条件下，汽车变速箱在给汽车轮传递最佳驱动力的过程中起着重要作用。变速箱通常分为手动变速箱（MTs）和自动变速箱（ATs）。手动变速箱换挡时，司机在踩下离合器踏板的同时，操纵换挡杆选择合适的挡位。自动变速箱变速则省去了这一系列的操作，自动变速箱可进一步分为自动换挡变速箱和无级变速箱（CVTs）。近年来，     

汽车自动变速箱过滤系统设计方法与试验研究

液压控制系统是电液控制自动变速箱的核心,而油液过滤系统正常工作是自动变速箱电液系统能够正常工作的基本保证。以某款自动变速箱为例,对比了不同油液环境下的自动变速箱电磁阀控制曲线,说明了油液污染带来的危害;分析了自动变速箱不同类型的过滤系统,阐明了过滤系统的设计过程及应重点注意事项,同时结合过滤试验方法和试验结果,说明了自动变速箱过滤系统的开发和试验过程。同时,针对自动变速箱的零件清洁度控制提出有效的辅助控制手段。     

基于小波分析的重载卡车变速箱装配品质在线检测方法研究

为确定某型变速箱装配品质,从变速箱内部结构出发,简要介绍了变速箱常见装配故障,从理论上分析了变速箱在各挡位情况下各齿轮和轴承等零件的常见故障特征频率,并搭建声压信号采集平台,采集变速箱不同挡位运转时产生的声压信号,利用小波阈值去噪法对采集的原始声压信号进行去噪,并运用小波分析对去噪后的声压信号进行分解,对相应的频段信号进行谱分析,结合理论分析与实验分析的结果,获得变速箱的装配故障特征,为检查变速箱装配品质提供依据。该研究对变速箱装配品质检测具有一定的参考意义。     

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。     

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.     

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.     

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.     

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.     

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。     

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...