相关分析在机械振动信号处理中的应用

信号的消噪处理和信号源识别是振动分析中的两个重要问题.首先介绍了相关性在信号滤波方面的应用,分析对比了相关性在消噪方面的应用范围、优点和不足,重点介绍了三重相关和多重相关的方法和研究发展情况;其次介绍了相关分析在振源和噪声源识别中的两种应用方法,着重介绍了偏相干方法的发展、应用、要注意的问题以及有待研究的问题;最后总结了相关分析在振动消噪和噪声源识别上的优缺点,指出了相关分析在振动信号处理中应用的发展趋势.     

基于流固耦合的水轮机振动分析

在流固耦合的基础上,对某一混流式转轮进行了振动分析,得出了叶片和转轮在空气中和水中的振型和频率,并比较了流量和离心力对转轮模态的影响.     

红外光谱法在润滑油分析中的应用与研究进展

综述了红外光谱法在润滑油分析和监测方面的应用与研究进展,重点介绍了近年来该方法在润滑油总酸值、总碱值和水含量方面的应用和研究情况,分析了该方法用于润滑油分析的优势和需要解决的问题,展望了该方法在我国润滑油分析中的应用前景。     

物联网和云计算在衡器上的应用

本文首先介绍了物联网和云计算的概念,然后分析了云计算给物联网在衡器上的应用带来的机遇,最后介绍了物联网和云计算在数字式汽车衡上的应用情况。希望可以抛砖引玉,推广物联网和云计算在衡器业内的应用。     

二相步进电动机细分驱动控制系统分析

二相步进电动机由于固有的振动和噪音,限制了其在工业领域的应用,本文分析了细分驱动器在减小振动和噪音方面的原理和特点,介绍了细分驱动器的原理,同时对细分驱动器在实际应用中的特性作了评价.     

激光加热辅助铣削钛合金TC4的有限元分析

研究了在激光加热辅助条件下的钛合金铣削机理,采用高斯分布热源模型作为热流量载荷,并考虑了钛合金材料的Johnson-Cook本构模型和Johnson-Cook失效断裂准则。建立了在激光加热辅助条件下铣削过程的顺序热力耦合有限元分析模型,计算了工件温度场分布和工件表面应力等。通过分析对比仿真和实验结果,在可接受的误差范围内,验证了模型的准确性,证实了模型的可行性和有效性。     

松质骨流-固-热多场耦合微流速渗流实验研究及数值分析

在达西定律基础上自主研制了松质骨流固热多场耦合微流速渗透率测量装置,利用该装置对猪股骨结节新鲜松质骨进行了渗透试验,得到了该材料在不同的压力和温度下的渗透率,并且和理论数据进行了对比.建立了松质骨在流-固-热多场耦合下孔隙度和渗透率随温度和压力变化的动态数学模型.分析了实验过程中温度和流体压力等因素对实验结果的影响,讨论了该试验装置的相关应用范围和发展前景.     

法国 另一个手表国度

我们习惯了在瑞士表中发现尖端和工艺,在德国表中体会严谨和考究。而法国表呢?在多了激情和快乐的注入,你会发现在这个国度,手表有了不一样的表情。她是符号,是变化,也是姿态。时间也因此变得激情和快乐。     

燃气轮机应用于地面武器装备的前景分析

结合燃气轮机的发展和应用情况,综述了燃气轮机发展现状及前景,特别探讨了其在军事装备领域的应用,提出了在地面武器装备中推广和应用燃气轮机技术的必要性和建议。     

莲子剥壳机研究现状

对莲子剥壳机在国内的发展情况进行了概括,在此基础上总结了该种机械在研究和生产中存在的突出问题。在参照莲子剥壳机已经取得的研究和应用成果的基础上,对该种机械以后大致的发展方向和趋势进行了总结。     

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.     

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。     

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。     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

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。     

RLS and LMS blind adaptive multi-user detection method and comparison in acoustic communication

RLS and LMS blind adaptive multi-user detection algorithm and multi-user detector was proposed to solve the problem of multi-user signal detection problem encountered in underwater acoustic communication networks.In simulation analysis,RLS and the LMS blind adaptive multi-user detector were designed and tested for synchronous and asynchronous multi-user communication process.The results of SIR comparison and MMSE comparison show that,both of the two methods can realize blind adaptive detection when any user change in multi-user communication,during this process,the training communication sequences are not needed.The RLS algorithm has about 5 dB higher in SIR compared with LMS algorithm,and the convergence velocity of RLS algorithm is also higher than LMS algorithm when the communication users change.RLS algorithm has better ability in multi-user detection than that of LMS algorithm,and it has great attraction and guiding significance for solving the problem of multiple access interference(MAI) in multi-user communication.     

Robust Impedance Control of Robots Using an Adaptive Interaction Force Observer

For robot interaction control,the interaction force between the robot and the manipulated object or environment should be monitored.Impedance control is a type ...     

Research on key techniques of expendable conductivity temperature depth measuring system

This paper analysis the developing of expendable conductivity temperature depth measuring system(XCTD)and introduce its principle of measuring about temperature,salinity and depth of ocean.Some key techniques are put forward.According to the real needs of XCTD,conductivity sensor with high sensitivity is designed by principle of electromagnetic induce,the ocean conductivity from induced electromotive force has been calculated.Adding temperature correction circuit would help to reduce error of conductivity measurement because of sharply changing temperature.Advanced temperature measuring circuit of high precision and the constant current source is used to weaken effect of self-heating of resistance and fluctuation of the source.On respect of remote data transmission,LVDS is a good choice for the purpose of guarantee the quality of data transmitted and the transmission distance is reaching to thousand meters in the seawater.Modular programming method is also brought into this research aimed at improve the stability,reliability and maintainability of the whole measuring system.In February,2015,the trials in South China Sea demonstrate that the developed XCTD realize effective measurement at a speed of 6 knots and detection depth at 800 m.The consistency coefficient of the acquired data is greater than 0.99 and the success rate of probe launching is above 90%.     

CHARACTERISTCS OF FLUID FILM IN OPTIMIZED SPIRAL GROOVE MECHANICAL SEAL

In order to investigate the sealing performance variation resulted from the thermal deformation of the end faces, the equations to calculate the fluid film pressure distribution, the bearing force and the leakage rate are derived, for the fluid film both in parallel gap and in wedgy gap. The geometrical parameters of the sealing members are optimized by means of heat transfer analysis and complex method. The analysis results indicate that the shallow spiral grooves can generate hydrodynamic pressure while the rotating ring rotates and the bearing force of the fluid film in spiral groove end faces is much larger than that in the flat end faces. The deformation increases the bearing force of the fluid film in flat end faces, but it decreases the hydrodynamic pressure of the fluid film in spiral groove end faces. The gap dimensions which determine the characteristics of the fluid film is obtained by coupling analysis of the frictional heat and the thermal deformation in consideration of the equilibrium condition of the bearing force and the closing force. For different gap dimensions, the relationship between the closing force and the leakage rate is also investigated, based on which the leakage rate can be controlled by adjusting the closing force.