工程起重机

正轮式起重机GJ20181030起重机用永磁同步电动机设计及有限元分析[刊,中]/曹小华…//起重运输机械.-2018,(1).-130～134基于具体工况下的起重机运行条件,运用永磁同步电机设计理论,设计出适合起重机低转速大转矩运行特性的永磁同步电机。利用Ansoft/Maxwell中RMxprt模块建立电机有限元模型,并基     

起重机用永磁同步电动机设计及有限元分析

基于具体工况下的起重机运行条件,运用永磁同步电机设计理论,设计出适合起重机低转速大转矩运行特性的永磁同步电机。利用Ansoft/Maxwell中RMxprt模块建立电机有限元模型,并基于二维瞬态电磁场对所建模型进行仿真研究,计算得到电磁转矩变化曲线和电感参数,不仅为起重机用永磁同步电机的结构优化提供方案,还为进一步研究低转速大转矩条件下永磁同步电机的控制策略提供理论基础。     

基于Ansoft的永磁同步电机建模与仿真

采用Ansoft公司的RMxprt和Maxwell 2D模型建立永磁同步电机模型,给出了电机的输入变换电路,构建一个完整的仿真系统。通过对PMSM模型的有限元分析,得出反电动势曲线,以及随转子位置变化的转矩及磁场分布情况。仿真结果为PMSM的优化设计及进一步研究提供了理论依据。     

基于Ansoft的通风机用永磁无刷直流电机设计与分析

采用Ansoft中RMxprt模块,对通风机用永磁无刷直流电机进行设计,得出了电机各部分的尺寸和相关参数,并采用Maxwell2D模块对该电机空载时的相关特性进行仿真和分析。最后对仿真结果与样机试验结果的各项性能指标进行了对比,验证了仿真模型和分析的准确性。     

基于MC9S12XS128的汽车电动助力转向控制器

针对EPS系统中存在有刷电机效率低、可靠性差的问题,采用永磁无刷直流电机作为助力电机;同时基于EPS系统的构成和工作原理,设计了MC9S12XS128型主控芯片为控制器内核的硬件电路,主要包括电机驱动电路、信号采集电路和最小系统电路;在助力电机的控制策略方面,结合EPS系统的助力控制目标,采用增量式PID算法控制电机扭矩;在程序设计方面,采用模块化的编写方式调试了EPS控制器的主程序以及各个模块的子程序,并添加了CAN通信模块以实现EPS控制器与整车的数据传输;最后对控制器进行了台架助力试验检测控制器和助力电机的运行情况,实验所测到的最大助力扭矩与设计最大助力扭矩误差小于1%。实验结果表明,无刷助力电机助力性能良好,达到预期助力目标,且控制器工作正常。     

空压机用高速电机电磁结构设计与仿真分析

针对燃料电池系统之供气子系统中的关键部件压缩机所使用的高速电机的结构设计和性能分析展开研究,完成符合应用要求的最优设计.针对具体空压机的应用,对比各种不同类型的电机,设计一款永磁同步高速电机.根据具体需求,确定电机设计方案,并在此基础上运用Ansofi软件完成对电机的建模;确定永磁同步电机的定转子结构以及气隙大小、永磁体充磁等具体参数,使其初步满足性能要求.然后对所得模型进行电磁特性有限元仿真,根据仿真结果不断优化电机结构.最后,针对所设计的高速电机气隙较大这一特点,通过RMxprt和Maxwell三维仿真计算对电机的端部漏磁情况做较为简单的结果分析.结果表明,电机端部的电磁特性的确发生了变化.     

基于Simplorer的无刷直流电机仿真分析

基于Simplorer和Maxwell软件仿真平台,对无刷直流电机及其控制方法进行联合仿真,该电机控制方法采用的是速度与电流双闭环控制。根据电机设计的技术性能指标,在Simplorer软件建立电机控制器模型,并通过其内部模块实现电机的控制算法;然后在Maxwell软件中的RMxprt模块建立电机模型,并生成Maxwell 2D有限元仿真模型;最后通过Simplorer的访问接口,实现Simplorer与Maxwell的联合仿真。通过该联合仿真能快速确定电机控制方案,是一种设计无刷直流电机控制方法的有效手段。     

基于RMxprt和Maxwell 2D对阀门电动装置电磁分析

RMxprt和Maxwell 2D为Ansys Workbench平台下的电磁模块。为保证电动装置符合阀门使用工况,可用RMxprt进行更合理的设计并用Maxwell 2D进行电磁分析。     

基于Ansoft RMxprt的三相永磁同步电机有限元分析

利用Ansoft软件对永磁同步电机的主要电磁参数进行估算,确定电机本体的定转子结构参数和绕组参数后,利用RMxprt模块对电机进行优化设计。按照给定的技术性能指标,对影响电机的参数进行分析,得到优化数据信息,确定电机的最优化结果。     

永磁同步电机的变频调速研究

无励磁损耗和自身体积较小是永磁同步电机的一大优势所在。本论文的主要目的是永磁同步电机进行建模与分析,基于ANSYS Maxwell建立外转子永磁同步电机的有限元仿真模型,并基于该模型对电机磁场及各项电磁性能进行仿真计算与分析,已达到对永磁同步电机变频调速研究的需求,对电机进行建模与分析。确定电机参数包括性能指标要求、定子、电枢绕组、转子参数,建立用外转子永磁同步电机的模型并对其进行参数计算和仿真,并对计算结果进行分析。     

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.     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.