共查询到20条相似文献,搜索用时 78 毫秒
1.
《机械设计与制造》2017,(12)
为了改善车辆平顺性和行驶安全性,设计了一种基于单出杆式磁流变减振器的汽车半主动悬架。在分析传统的磁流变减振器力学模型的基础上,提出了一种改进的磁流变减振器多项式模型,试制了磁流变减振器样机,进行了磁流变减振器的力学特性试验,设计了半主动悬架天棚控制器、地棚控制器和LQG控制器,进行了不同控制策略的对比仿真分析,开发了磁流变半主动悬架试验测试系统,开展了该磁流变半主动悬架的LQG控制台架试验测试。结果表明,所研制的磁流变减振器耗能效果良好,能够最大限度地发挥振动衰减功能。与被动悬架相比,在4Hz和5Hz正弦激励下磁流变半主动悬架的簧载质量加速度分别降低15.80%和23.36%,在随机路面激励下簧载质量加速度降低19.46%。 相似文献
2.
针对兼顾汽车行驶平顺性和馈能特性的需求,提出了一种新型磁流变互联悬架模型.先构建磁流变减振器力学与馈能的理论模型,并通过Simulink软件搭建磁流变减振器模型和磁流变互联悬架模型,分析影响馈能特性的主要参数;基于整车仿真模型,以30 km/h车速和一段C级路面为激励输入,对磁流变互联悬架与传统液压互联悬架进行对比仿真,分析互联悬架在实际路面激励下馈能特性和汽车行驶平顺性的变化规律.结果表明:磁流变互联悬架的减振效果更好;在满足车辆行驶平顺性需求的前提下,具有有效回收互联悬架振动能量和提高抗俯仰侧倾的能力. 相似文献
3.
4.
针对现有车用磁流变减振器(MRD)低频时阻尼力很小的问题,设计一种基于剪切模式的旋转式磁流变减振器,使减振器具有磁流变液用量小、低频时也具有大阻尼的性能,不仅能改善车辆的平顺性,也能提高车辆的操纵稳定性。进行了减振器的结构设计,利用ANSYS软件对磁场进行了有限元分析,以多学科优化软件ISIGHT为平台,以初步设计的减振器结构模型为对象,联合CATIA、MATLAB软件,对减振器的结构进行自动优化设计。采用SIMULINK软件对减振器外特性进行了仿真,结果表明,所设计的磁流变减振器在速度接近于零时就可达到很大的阻尼,可为车辆侧倾控制提供足够的阻尼力。 相似文献
5.
基于磁流变减振器的汽车悬架振动控制 总被引:5,自引:1,他引:5
分析了磁流变减振器特性,为了抑制汽车磁流变悬架的振动,提出了一种含有控制级和协调级的分级模糊控制。在控制级,把天棚、地棚混合控制策略与模糊智能控制策略相结合,设计了1/4车辆垂直振动的半主动模糊智能控制器;在协调级,设计了整车控制的协调器,根据反馈变量对整车4个独立模糊智能控制器输出参数进行调整。把某微型汽车的4只被动减振器改装成磁流变减振器,搭建了磁流变悬架全车测控系统,运用设计的分级模糊控制器,进行了平顺性随机输入实车道路试验。试验结果表明对汽车磁流变悬架的垂直振动进行分级模糊控制是可行的,能有效提高汽车的乘坐舒适性和操纵稳定性。 相似文献
6.
针对军用越野汽车在坏路面行驶中平顺性及操稳性提升的问题,首先建立了设计的一款单出杆双筒双线圈磁流变减振器的理论模型,经过理论仿真和台架试验研究了其示功特性和阻尼特性;设计了基于模糊算法的八板块控制算法,分别在B级路面、D级路面、波形路面上进行了平顺性试验,结果表明和被动减振器相比,驾驶员处振动强度下降达(14~20)%。在蛇形试验中,车身侧倾角、侧向加速度和横摆角速度下降幅值达(10~40)%。在制动试验中车身俯仰角下降幅值达(30~42)%。通过整车试验说明研制的单出杆双筒双线圈磁流变减振器以及控制策略对于提高军用越野汽车的平顺性和操稳性是可行的、有效的。 相似文献
7.
建立较为精确的磁流变减振器阻尼力模型是设计控制策略并获得良好控制效果的关键。基于流体动力学理论和磁流变液流变特性,对阻尼通道内磁流变液进行流体动力学分析,详细推导磁流变减振器阻尼力模型。结合阻尼通道处磁场有限元分析,完善阻尼力模型。最后试验测试自制磁流变减振器在不同励磁电流和不同活塞速度下的示功特性和速度特性,利用试验数据对模型进行系数辨识,建立磁流变减振器简化力学模型。研究结果表明,励磁电流小于0.8 A时,输出阻尼力试验值与计算值较吻合,当励磁电流增大,阻尼力试验值与计算值最大相差约100 N,计算值相对于试验值的误差在19%以内,该简化力学模型能描述磁流变减振器的基本力学特性,能为半主动悬架控制研究提供理论指导。 相似文献
8.
9.
10.
11.
Clarence W.DE SILVA 《Instrumentation》2019,(4):72-84
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... 相似文献
12.
INTEGRAL EQUATION METHOD'S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES 总被引:1,自引:0,他引:1
LI Cheng ZHENG Yanping 《机械工程学报(英文版)》2008,21(6):115-118
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. 相似文献
13.
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. 相似文献
14.
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... 相似文献
15.
分布动态载荷识别的抗噪处理 总被引:2,自引:2,他引:0
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. 相似文献
16.
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。 相似文献
17.
The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar... 相似文献
18.
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.... 相似文献
19.
J. A. Williams 《Lubrication Science》1997,3(3):267-306
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. 相似文献
20.
M. Stedman 《Journal of microscopy》1988,152(3):611-618
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. 相似文献