液黏调速变矩器液压回路分析及试验研究

液黏调速变矩器性能优异,不仅可以无级调节原动机输出转速,改变输入功率,还可以自适应复杂多变的工况,因此广泛应用于抓斗式挖泥船。液压控制系统主要负责调节摩擦片压紧油压及变矩器内压,系统比较复杂,许多挖泥船都是因为液压控制系统的原因不能正常工作。针对这种情况,对液黏调速变矩器液压控制系统进行了分析,介绍了系统中各个阀件的功能,并通过试验模拟了液黏调速变矩器的各种工作工况,分析了各工况中液压回路油压的变化规律。试验结果表明,对液黏调速变矩器液压控制系统的研究是正确的,为液黏调速变矩器的维护、维修提供了指导。     

液压绞车电液比例伺服控制系统仿真研究

分析了电液比例伺服阀的特点及电液比例伺服阀控变量泵容积调速系统的工作原理。利用AMESim软件,建立了液压绞车电液比例伺服控制调速系统的仿真模型。利用该模型对系统的性能进行了仿真研究,表明该调速系统具有很好的速度跟踪特性,较高的速度控制精度以及较好的系统工作稳定性。     

基于AMESim/MATLAB的四缸同步回路仿真研究

伺服四缸液压同步回路是大型钢板轧机、沙模铸造机液压系统中的关键单元。利用Matlab和AMESim两款仿真软件各自的优点,通过接口的设置,分别建立了伺服阀控四缸同步回路的液压系统及其控制系统模型。通过合理的将液压缸位移反馈到伺服阀的控制输入端,经过优化得到了最佳的反馈增益。液压缸达到了理想的速度、位移、加速度同步效果。为大型同步液压系统建模仿真提供了一种新的研究策略。     

电子限滑差速器电液控制系统特性研究

 以某电子限滑差速器（ELSD）中的电液控制系统为研究对象，分析其电液回路的控制原理及响应特性。根据回路各部件间的机、电、液联动关系，建立系统的数学模型。并运用AMESim/Simulink建模仿真平台，搭建ELSD的液压仿真模型。基于该模型，分析ELSD活塞输出压力与脉宽调制（PWM）信号控制的高速开关阀之间的动态响应关系。研究PWM信号频率、占空比、车轮间转速差及差速器、高速开关阀设计因素对输出油压的影响。通过分析仿真实验结果，提出提高该系统响应速度及控制精度的方法。     

液粘调速离合器摩擦副散热稳态流场仿真分析

液粘调速离合器是依靠液体剪切力来传递转矩和调节转速的新型传动装置。可作为理想的调速、稳速、功率分配以及柔性启动装置。本文应用流体仿真软件STAR-CCM+对液粘调速离合器摩擦副的内部稳态流场建立模型、生成网格、物理模型参数和边界条件设置、仿真计算,获得流场出口平均油温,并通过试验,验证了仿真计算精度。通过对获得的温度场和流速场分析,发现摩擦片油槽方向对散热效果影响很大,建议结合离合器的旋转方向,对油槽方向进行优化设计。     

伺服阀控非对称缸的压力跃变分析与仿真

本文首先对液压伺服阀控非对称缸系统进行数学建模,分析计算了伺服阀控非对称缸在换向时产生的压力跃变,用AMESim仿真软件对系统进行了仿真,得出压力跃变曲线。最后设计了差动控制回路来解决阀控非对称缸的压力跃变问题。     

基于AMESim的抓斗采矿船液粘调速系统仿真

阐述了液粘调速离合器的原理及其在抓斗采矿船动力传动系统上的应用,利用AMESim动力仿真软件对抓斗采矿船的动力传动系统进行建模,调节元件模型参数,优化模型。通过仿真抓斗采矿船的一个典型工作循环,得到了系统的动态性能曲线。通过分析仿真结果,验证了液粘调速离合器的作用效果及模型的有效性。     

基于 AMESim 的抓斗采矿船液粘调速系统仿真

阐述了液粘调速离合器的原理及其在抓斗采矿船动力传动系统上的应用,利用AMESim动力仿真软件对抓斗采矿船的动力传动系统进行建模,调节元件模型参数,优化模型。通过仿真抓斗采矿船的一个典型工作循环,得到了系统的动态性能曲线。通过分析仿真结果,验证了液粘调速离合器的作用效果及模型的有效性。     

基于AMESim的喷嘴挡板伺服阀动态性能分析

喷嘴挡板伺服阀的动态性能关系到电液调速系统的控制精度和响应速度。根据挡板组件、阀芯套件的运动规律,推导出了挡板的位移偏移与控制滑阀位移的函数关系和动态平衡方程。结合某型伺服阀的相关参数,采用AMESim软件建立了喷嘴挡板伺服阀动态模型,仿真结果表明:伺服阀具有超快的响应、较高的灵敏度、良好的油压稳定性和稳定的动态跟随性能;系统在阶跃响应下,挡板与喷嘴的间隙能快速准确地回到初始位置保证了稳定初调速度。分析了伺服阀内部状态变量的灵敏度特征,为喷嘴挡板伺服阀结构参数优化和动态性能分析提供了理论依据。     

矫直机液压压下装置伺服系统的建模与仿真

文章的研究对象是矫直机液压压下系统。针对伺服阀控制增压缸结构建模 ,建立了力反馈伺服控制系统的传递函数 ,并对系统进行MATLAB仿真和对其性能进行了分析。     

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...     

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。     

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...     

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。     

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。     

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.     

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...