汽车阻尼可调减振器比较分析

阐述了减振器的作用和工作原理,比较分析了电、磁流变液减振器、机械调节阻尼可调减振器、电机控制阻尼可调减振器、电磁阀控制阻尼可调减振器与干摩擦式阻尼可调减振器的结构与特点,展望了减振器技术的发展前景。     

两级阻尼可调式液压减振器的性能仿真与试验

可调阻尼减振器是汽车半主动悬架的关键部件.根据某大客车电控半主动悬架的阻尼控制要求,以该车原被动式液压减振器为基础,设计出一种具有两级阻尼特性的可调减振器.采用共轭梁法计算节流阀片的挠曲变形,建立该减振器阻尼特性的数学模型,仿真分析活塞杆直径,阻尼阀孔径以及调节孔孔径等主要结构参数对减振器阻尼性能的影响,在此基础上确定可调减振器的主要设计参数.对研制的可调减振器样件进行阻尼性能测试,结果表明:减振器的两级阻尼状态变化明显,阻尼切换控制准确,阻尼力试验值与仿真值的偏差小于8%,说明所建的减振器数学模型具有较高的精度,采用共轭粱法计算节流阀片挠曲变形是可行有效的,为设计开发可调阻尼液压减振器和研究汽车半主动悬架提供了重要依据.     

大客车空气悬架可调式液压减振器设计与试验

根据某大客车空气悬架的阻尼控制要求,确定了减振器在"软"、"硬"阻尼状态下的阻尼力设计目标,设计了以电磁阀和摆动气缸作为驱动机构的电控气动式可调阻尼减振器,介绍了该减振器的结构组成、工作原理,通过仿真计算分析了该减振器的阻尼特性.研制了可调阻尼减振器样件并进行了台架性能测试,减振器阻尼力试验结值与仿真值、设计目标值基本一致.进行了大客车道路平顺性对比试验,结果表明,采用可调式液压减振器使大客车的舒适性界限值TCD由原车的2.8 h提高到4.2 h,说明可调减振器设计方案可行,满足了大客车空气悬架的阻尼控制要求.     

一种可调阻尼减振器的设计与试验研究

对可调阻尼减振器的设计理论与实现方法进行了分析,为从实践上进一步验证可调阻尼减振器的动态特性,设计出一种节流口可调的减振器及其台架试验测试系统,通过试验获得各个工况的减振器的阻尼力-速度特性曲线,依据试验数据建立减振器阻尼力与步进电机转角之间的非线性关系,为半主动悬架控制器的阻尼控制规律设计提供依据。     

可调阻尼式汽车减振器设计与试验研究

针对目前被动减振器不能根据路况改变阻尼的问题,设计了一种节流口式可调阻尼减振器,介绍了该减振器的结构组成和工作原理,详细阐述了可调阻尼减振器的设计方案,并分析了步进电机与节流口的关系以及力与速度特性计算。根据首批可调阻尼减振器样件,对可调节流口当量面积设计这一关键问题进行了讨论,理论分析结果为可调阻尼减振器的制作提供了依据,并对改进后的可调阻尼减振器样件进行了台架试验。试验结果表明所设计的可调阻尼减振器阻尼力曲线较为饱满平滑,无明显畸变,阻尼力随节流口开度变化较明显,且与步进电机转角成对应关系,符合设计和使用要求。     

回转叶片式磁流变减振器阻尼特性分析

介绍了回转叶片式磁流变减振器的结构和工作原理,基于平板模型得出了其阻尼力和阻尼可调系数的计算公式.对自行研制的回转叶片式磁流变减振器的阻尼可调系数与阻尼孔内流速的关系等进行了理论分析．通过深入分析该型减振器的阻尼特性,为其在车辆悬挂系统半主动控制中的应用奠定了基础．     

电磁阀式阻尼可调减振器AMESim建模研究

以某种电磁阀式阻尼可调减振器为研究对象,通过实物拆解和对其结构原理进行分析,根据减振器节流孔油液流动及开阀压力,分别推导电磁阀式阻尼可调减振器在伸张行程和压缩行程的阻尼力计算公式。对拆解的电磁阀式阻尼可调减振对其阀口及阻尼孔进行测量,借助AMESim软件搭建减振器精细模型,并将该可调减震器AMESim仿真模型的力学特性与可调减震器实物的力学特性对比,验证模型的正确性。对此类电磁阀式阻尼可调式减振器模型的建立对研究汽车半主动悬架的控制具有重要意义。     

汽车液压减振器设计研究

阐述了可调阻尼液压减振器的设计方案,对可调阻尼减振器性能进行了理论分析,针对减振器拉伸和压缩阶段各进行了力-速度特性计算,推导出数学关系式,在原车被动液压减振器的基础上,改进设计了一种节流口式可调阻尼液压减振器,并对此进行了台架试验。试验结果表明:所研制的可调阻尼液压减振器阻尼力与步进电机转角成对应关系,符合设计和使用要求。     

筒式液阻减振器的阻力特性及其发展状况

介绍了目前使用在车辆上的各种不同结构形式的减振器,分析了诸如橡胶、金属弹簧、电流变液和磁流变液、气体控制阻尼可调、干摩擦式阻尼可调等类减振器的结构特点、工作原理、适用场合及其优缺点;给出了双筒液压减振器的复原阻力与压缩阻力的计算方法,为液阻减振器的设计制造提供了理论基础;最后,分析了我国筒式液阻减振器技术的发展状况及其存在问题,展望了减振器技术的发展前景.     

阻尼连续可调减振器性能研究

为了研究某阻尼连续可调(CDC)减振器的实际减振能力,在分析该减振器的工作过程及阻尼调节原理的基础上,通过实验的方法获得了不同控制电流下的阻尼特性曲线。结果表明:在振幅25 mm、振动速度为0.524 m/s的正弦冲击条件下,未通电时CDC减振器的阻尼值为最大;随着控制电流的增大,阻尼值在不断减小;复原和压缩行程阻尼力的可调范围分别为754～2825 N和917～2430 N,而阻尼调节阀控制电流的有效范围为0.75～1.5 A;控制电流的增加会使阻尼力与速度的关系由非线性趋于线性转换。试验结果可为该CDC减振器的实际应用及ECU控制模块的设计与调校提供参考依据。     

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.     

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....     

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。     

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.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.