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1.
汽车磁流变半主动悬架的模糊控制 总被引：1，自引：0，他引：1
为带有磁流变液智能阻尼器的半主动汽车悬架系统设计了一种模糊控制器：将半主动悬架相对位移的误差及误差变化率作为模糊控制器的输入,阻尼力作为其输出,利用磁流变液智能阻尼器的阻尼力随电流变化的特性使车身的振动降到最小。仿真实验给出了最优被动悬架和模糊控制智能半主动悬架在随机路面激励情况下的响应曲线,结果表明,磁流变半主动悬架系统采用模糊控制效果较理想,其车身垂直加速度等参数变化幅度也有所降低。 相似文献
2.
磁流变液是未来应用最广泛的智能材料之一,它在无外加磁场作用下表现出良好的流体特性,在强磁场的作用下它的粘度会在毫秒级的时间内增加两个数量级以上,表现出类似固体的特性,一旦去掉磁场又立刻恢复液体的特性.这种可逆、迅速、易控的特点使磁流变液在机械工程中得到广泛的应用,其中包括表面光整加工,如将其用于光学镜片的表面研磨.目前其加工对象仅限于非导磁性材料,而现在绝大多数的机械零件的材料为导磁性材料.文章明确了磁流变液光整加工方法的主要优点;根据加工机理分析和初步实验研究,概括出将磁流变液用于导磁性材料表面光整时碰到的具体问题,并有针对性地提出了合理的解决方法. 相似文献
3.
磁流变液是一种流变特性随施加磁场强度大小和方向而变化的粘性流体,磁流变阻尼器是一种智能型主动控制的执行装置,在汽车行业已经引起高度关注,国内外相关专家对其进行了广泛研究。本文详细综述了磁流变阻尼器动力学模型的研究现状,分析了各种模型的优缺点,讨论了目前磁流变阻尼器研究中有待解决的问题。认为有必要加强减振器结构参数、振动信号特性、负载等与所需阻尼力关系的研究,加强神经网络和模糊逻辑等现代智能控制技术在磁流变阻尼器控制方面的研究,这是解决磁流变技术工程应用问题的有效途径。 相似文献
4.
用磁流变液实现导磁材料机件表面的光整加工 总被引：1，自引：0，他引：1
磁流变液是未来应用最广泛的智能材料之一，它在无外加磁场作用下表现出良好的流体特性，在强磁场的作用下它的粘度会在毫秒级的时间内增加两个数量级以上，表现出类似固体的特性，一旦去掉磁场又立刻恢复液体的特性．这种可逆、迅速、易控的特点使磁流变液在机械工程中得到广泛的应用，其中包括表面光整加工，如将其用于光学镜片的表面研磨．目前其加工对象仅限于非导磁性材料，而现在绝大多数的机械零件的材料为导磁性材料．文章明确了磁流变液光整加工方法的主要优点；根据加工机理分析和初步实验研究，概括出将磁流变液用于导磁性材料表面光整时碰到的具体问题，并有针对性地提出了合理的解决方法． 相似文献
5.
由于磁流变液具有很高的黏度,混入其中的气泡很难被排除干净,从而导致磁流变阻尼器产生力滞现象,为了分析混入空气对磁流变阻尼器半主动控制效果的影响,开展了磁流变阻尼器在不同工况下的力学性能试验,分析了电流、位移幅值和激励频率对力滞现象的影响.采用简化的Bouc-Wen模型和一小刚度弹簧来模拟试验中由于混入空气导致的力滞现象,并采用基于加速度反馈的clipped-optimal控制策略对一个加入磁流变阻尼器的单自由度结构进行了半主动控制分析.数值结果表明:混入的空气会降低磁流变阻尼器的半主动控制效果,随着混入空气含量的增加,磁流变阻尼器的半主动控制效果会逐渐趋于passive-off控制下的被动减震效果. 相似文献
6.
从三自由度超声波电机的原理与基本结构出发,先分析转子在静止情况下的力矩,接着分析转子在旋转情况下的力矩．随后通过转子转动时动平衡关系得到了求解摩擦驱动力矩和摩擦阻力矩的方法．最后,通过仿真结果对本文提出的数学模型做了初步验证,得到了一些有益的结果． 相似文献
7.
就"转柱法测液体粘度"实验中的侧面粘滞力矩、端面粘滞力矩和摩擦力矩对实验的影响进行了讨论;特别是导出端面粘滞力矩的计算公式,用它进行误差修正效果明显. 相似文献
8.
单相电容式电机是日常生活最常用的电机，很多学生不清楚它的工作原理，更缺乏这方面的演示模型。三相交流电机三个电枢可以产生的合磁感应强度B是大小不变，而方向不断旋转的磁场。转子不断与磁场发生相对运动，产生感应电流，感应电流又受到磁场的作用，产生转动力矩，从而使转子转动起来。其实单相电机也是靠两线枢产生的大小不变而方向不断发生变化的磁场使转子转动的。如何制作这样的模型，用它产生旋转磁场呢?下面作一简单的介绍： 相似文献
9.
为了研究摩擦力矩对于汽车轮毂轴承的影响规律,针对某型号的双列球型轮毂轴承,采用国内某公司生产的摩擦力矩测试机,对轮毂轴承单元进行摩擦力矩的测试实验.通过分析实验数据,并与产品的设计要求进行对比,得出产品产生摩擦力矩的范围和规律.同时测试了轮毂轴承单元在一定预紧力作用下,其摩擦力矩转速的变化.本研究对于轮毂轴承单元的产品测试提供了一条途径,同时对研究摩擦力矩的影响因素及其规律提供了一种思路. 相似文献
10.
对交流电机转子横振时电磁阻尼及考虑电磁阻尼时转子横振进行了研究.首先应用磁场理论求得了电机三相不对称运行时电磁阻尼力,并对三相对称时的电磁阻尼进行了计算.接着用拉格朗日-麦克斯韦方程求得了转子横向振动的方程,画出了三相对称时转子强迫振动的幅频曲线,并与实验进行了对照,实验结果与理论结果吻合的很好. 相似文献
11.
祝长生 《浙江大学学报(A卷英文版)》2003,4(5)
A disc-type magneto-rheological fluid damper operating in shear mode is proposed in this paper, which is based on the special characteristics of the magneto-rheological (MR) fluid with rapid, reversible and dramatic change in its rheological properties by the application of an external magnetic field. The magnetic field of the disc-type MR fluid damper is analysed by the finite element method; the controllability of the disc-type MR fluid damper on the dynamic behaviour of a rotor system; and the effectiveness of the disc-type MR fluid damper in controlling the vibration of a rotor system, are studied in a flexible rotor system with an over-hung disc. It is shown that the magnetic flux density of the disc-type MR fluid damper in the working areas can significantly change with the applied current in the coil; and that the dynamic behavior of the disc-type MR fluid damper can be varied by the application of an external magnetic field produced by a low voltage electromagnetic coil. The disc-type MR fluid damper can significantly change the dynamic characteristics of a rotor system, provided that the location of the disk-type MR fluid damper is carefully chosen. The disc-type MR fluid damper is a new actuator with good dynamic characteristics for rotating machinery. 相似文献
12.
INTRODUCTIONElectro rheological (ER ) Magneto rheologi cal(MR)fluidisakindofcontrollablefluidwhoserheologicalproperties,especiallyapparentviscosity,canbedramaticallyandreversiblyvariedinafewmillisecondsbytheapplicationofanexternalelectrical magneticfield… 相似文献
13.
Zhu Chang-sheng 《浙江大学学报(A卷英文版)》2003,4(5):514-519
A disc-type magneto-rheological fluid damper operating in shear mode is proposed in this paper, which is based on the special
characteristics of the magneto-rheological (MR) fluid with rapid, reversible and dramatic change in its rheological properties
by the application of an external magnetic field. The magnetic field of the disc-type MR fluid damper is analysed by the finite
element method; the controllability of the disc-type MR fluid damper on the dynamic behaviour of a rotor system; and the effectiveness
of the disc-type MR fluid damper in controlling the vibration of a rotor system, are studied in a flexible rotor system with
an overhung disc. it is shown that the magnetic flux density of the disc-type MR fluid damper in the working areas can significantly
change with the applied current in the coil; and that the dynamic behavior of the disc-type MR fluid damper can be varied
by the application of an external magnetic field produced by a low voltage electromagnetic coil. The disc-type MR fluid damper
can significantly change the dynamic characteristics of a rotor system, provided that the location of the disk-type MR fluid
damper is carefully chosen. The disc-type MR fluid damper is a new actuator with good dynamic characteristics for rotating
machinery.
Project supported partially by the EC BRITE/EURAM program under BRPR-CT97-0544 IMPACT project and State Key Laboratory of
Vibration, Shock and Noise, Shanghai Jiatong University 相似文献
14.
Experimental Study on Magnetorheological Damper for Semi-Active Vibration Control of Civil Infrastructures 总被引：3，自引：0，他引：3
Magnetorheological (MR) fluid is a kind of smart material whose rheological properties can be rapidly varied in magnetic field. To make full use of the advantages of MR fluid to devices, a model of double-ended,shear-combined and valve-typed MR damper is designed and manufactured, and the dynamic properties under sinusoidal excitations are experimentally studied. The experiment results show that the maximum damping force of the MR damper at the full magnetic intensity reaches about 20 k while the maximum power required is less than 50W, which predicts that the MR damper will be a powerful measurement for semi-active vibration control of civil infrastructures. 相似文献
15.
The passive electromagnetic damper has the same configuration as that of the electromagnetic bearing, but no sensors and no closed loop control are needed. Its robustness and no-contact structure are its great advantages. When the rotor vibrates, the electromagnetic field intensity in the air gap is altered, then fluctuating currents in the damper coils and eddy currents inside the surface layer of rotor are created. Damping force is caused by the fluctuating currents, while retardation torque is generated by eddy currents. The characteristics of a damper may be improved by adding an additional electrical circuit. Numerical studies showed that damping coefficient increases with increasing static current, but decreases with increasing frequency. And the damping coefficient of the improved damper at higher frequency is more evident than that of the original damper. Experimental results showed that the resonant vibration around the first critical speed was obviously suppressed by both types of passive electromagnetic damper. 相似文献
16.
The effects of journal misalignment on the transient flow of a finite grooved journal bearing are presented in this study.
A new 3D computational fluid dynamics (CFD) analysis method is applied. Also, the quasi-coupling calculation of transient
fluid dynamics of oil film in journal bearing and rotor dynamics is considered in the analysis. Based on the structured mesh,
a new approach for mesh movement is proposed to update the mesh volume when the journal moves during the fluid dynamics simulation
of an oil film. Existing dynamic mesh models provided by FLUENT are not suitable for the transient oil flow in journal bearings.
The movement of the journal is obtained by solving the moving equations of the rotor-bearing system with the calculated film
pressure as the boundary condition of the load. The data exchange between fluid dynamics and rotor dynamics is realized by
data files. Results obtained from the CFD model were consistent with previous experimental results on misaligned journal bearings.
Film pressure, oil film force, friction torque, misalignment moment and attitude angle were calculated and compared for misaligned
and aligned journal bearings. The results indicate that bearing performances are greatly affected by misalignment which is
caused by unbalanced excitation, and the CFD method based on the fluid-structure interaction (FSI) technique can effectively
predict the transient flow field of a misaligned journal bearing in a rotor-bearing system. 相似文献
17.
磁悬浮（无轴承）电机利用磁场力使转子悬浮并驱动其实现高速或超高速旋转．基于传统电机技术提出一种交流圆弧电机原理,并按电磁轴承悬浮技术,水平方向对称于转子布置2个圆弧电机,垂直方向对称于转子布置2个圆弧电机,构成交流磁悬浮感应电机;建立电机在干扰作用下转子与定子间的间隙（气隙长度）变化规律,基于电磁理论建立了气隙磁感应强度的分布规律,利用虚位移原理建立电机电磁悬浮力和电磁转矩数学模型;通过有限元分析对磁感应强度、电磁悬浮力和电磁转矩等分布特性进行了仿真研究． 相似文献
18.
无轴承电机是利用磁悬浮轴承和交流电机结构的相似性,将产生磁悬浮力的磁悬浮轴承绕组置入电机定子,省去了专门的磁悬浮轴承．通过对转矩绕组和悬浮力绕组的解耦控制,使电机的转子同时具有产生转矩和自悬浮的功能．无轴承电机能够实现高速、无摩擦等优良性能,是当前研究的热点之一,无轴承电机悬浮控制系统设计是该研究的关键．本文介绍了无轴承电机悬浮控制的基本原理,设计了基于转矩绕组转子磁场定向的悬浮控制系统． 相似文献
19.
Fluent作为计算流体动力学（CFD）常用的商用软件,它可以对包含有流体流动和热传导等相关物理现象的系统做出分析,特别适用于极其复杂问题的流场.文中首先根据所设计的减振器建立数学模型,求出阻尼力的计算公式,接着采用GAMBIT软件建立减振器模型,并在Fluent中导入该模型,设置相关的参数及边界条件对该减振器进行数值分析.然后对结果进行分析,进而与理论模型的结果进行比较,最后对该减振器的性能进行了总结,并对其结构提出了几点建议. 相似文献