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针对传统涡轮增压器超高速轴承-转子系统动力学建模精度不高、模态参数不易识别等问题,基于Timoshenko梁理论建立了涡轮增压器动力学模型及运动微分方程,利用锤击法试验对增压器不同激励位置、有无预紧力等工况下的模态参数进行了识别,并将理论与试验分析结果进行了对比验证。研究结果表明:激励涡轮增压器不同位置时,系统的激发模态不尽相同;预紧力对转子动力学分析结果具有重要影响,增加预紧力可显著提高转子刚度;建立的动力学模型和模态识别方法具有一定的准确性和适用性,可以为后续涡轮增压器结构优化设计、模态参数识别提供理论与试验基础。 相似文献
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转子作为旋转机械的核心部件,对其进行精确的动力学分析是获得整个系统动力学特性的关键,而模态分析作为动力学分析的基础,对转子系统的设计、特性的研究以及故障时的分析等尤为重要。运用Solid Works对磁轴承转子部件进行了三维建模并结合Co SMo SWorks在自由与受迫两种不同状态进行了分析与比较,得到了该轴系的固有频率及相对应的振型图。同时考虑了轴承支撑、离心力、电机扭矩对轴系一阶固有频率的影响,意在为进一步分析磁轴承转子系统的动态特性打下坚实基础。 相似文献
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基于反馈线性化和保性能控制的轴向磁轴承单侧线圈故障容错控制 总被引:1,自引:0,他引:1
针对轴向永磁偏置磁轴承一侧线圈无电流时磁轴承承载能力下降且非线性增强的情况,提出一种反馈线性化与保性能控制相结合的组合容错控制策略来提高轴向磁轴承在故障情况下的承载能力并使其能在承重时稳定悬浮转子。首先,建立了故障情况下后轴向磁轴承-转子系统的非线性动力学模型,通过反馈线性化方法使系统大范围线性化。然后,在考虑参数摄动的基础上设计最优保性能控制器使转子稳定悬浮。最后,在轴向一侧线圈无电流的永磁偏置磁悬浮转子上进行了多项实验。实验结果表明,所设计的组合容错控制器实现了承重情况下转子的稳定悬浮,摄动最大的参数变化约35%时位移跳动量峰值为2.6μm,超调量小于3%,调节时间为82ms。结果验证了该方法不仅能实现容错控制,而且具有良好的动静态性能及鲁棒性。 相似文献
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伴随着高速透平机械向大跨度、柔性结构方向发展,转子-轴承系统的稳定性将面临着严峻考验。在出厂测试阶段,确保机组转子系统具有足够稳定性裕度是降低生产现场机组发生失稳故障风险的重要手段。采用适用于随机平稳环境激励下的随机子空间法,对机组的模态参数进行辨识,可规避在转子非驱动端增设电磁激振器的传统测试方法。通过分析转子振型进动方向,区分一阶正反进动的模态参数。结合3-σ统计聚类算法,剔除非稳定的噪声或物理极点,形成了区分转子系统的正反进动的稳态图。数值仿真表明,随机子空间法可以有效地辨识系统的模态参数,利用旋转机械的振型进动方向分析方法可以区分正反进动。此外,通过传统扫频激励模态参数辨识试验,验证了随机子空间方法的辨识精度和工程测试可行性。研究结果可为透平机组的稳定性测试提供技术和理论支撑。 相似文献
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为抑制主动磁轴承中基座的运动造成转子的振动增大,设计并实现了一种基于惯性运动的前馈控制方法。首先,针对基座运动状态下的磁轴承系统,建立了基座运动的五自由度磁轴承转子动力学模型,然后,分析了在基座进行小幅度复杂运动时转子受扰动力的动力学,提出了一种基于自适应算法的惯性前馈方法。最后,采用搭建的实验平台对不同扰动下开启前馈控制前后转子的响应进行了实验研究。实验结果表明:自适应前馈控制器使能后,磁轴承转子的位移减少了80%以上。设计的自适应前馈控制方法能够有效抑制磁悬浮系统基座扰动对转子振动的影响,大幅提高了磁轴承转子的运行精度,且设计的系统仅需增加一个小体积的惯性微机电测量单元,满足实际工程应用需求。 相似文献
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调研了保护轴承-转子系统非线性动力学研究领域内近30年来的代表性成果。首先,梳理了局部碰撞模型的发展历史,分别从转子和保护轴承两方面对系统结构模型的发展进行了综述,并给出了各模型的特点;接着,从跌落响应形态切入,重点分析了保护轴承-转子系统损伤的最主要原因——后向涡动;然后,从转子结构、轴承结构和轴承参数三个方面,分析了跌落响应结果与系统结构及接触参数的关系;最后,通过总结归纳,给出了保护轴承结构和参数设计选用的通用准则,并提出了后续值得深入研究的几点问题。 相似文献
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The nonlinear dynamic behavior of a rigid rotor supported by a spiral-grooved opposed-hemisphere gas bearing is investigated in this article, focusing particular attention on its whirl motion. The finite element method combined with the finite difference method is employed to solve the time-dependent Reynolds equation that is coupled with the rotor motion considering five degrees of freedom. The rotor responses to the initial disturbance and synchronous and nonsynchronous excitations are investigated. To analyze the complicated dynamic behavior of the rotor–bearing system, the trajectories of the rotor centerline, time responses, phase portraits, power spectra, Poincare maps, and bifurcation diagrams are obtained from the numerical procedure. The results show that the conical whirl instability appears earlier than the cylindrical whirl instability with increasing rotational speed for the rotor–bearing system with no unbalance mass. Moreover, it reveals that the complex dynamic behavior of the system excited by unbalance mass varies with rotational speed and rotor mass. In addition, bifurcation diagrams employing the rotating speed and rotor mass as bifurcation parameters are obtained. Finally, the nonsynchronous excitation responses are presented, which behave in a different way than the synchronous excitation responses. The results of this study offer a further understanding of the nonlinear characteristics of spiral-grooved opposed-hemisphere gas bearings. 相似文献
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主动电磁轴承失效后转子坠落在备用轴承过程中的非线性动力学 总被引:3,自引:0,他引:3
用有限元法建立了任意个由滚动轴承组成的固定间隙备用轴承-主动电磁轴承-多盘多质量转子系统在主动电磁轴承失效前后的动力学方程,以一个多盘转子系统为例分析了主动电磁轴承失效后转子坠落在备用轴承过程中的瞬态非线性动力学特性,讨论了柔性备用轴承的支撑刚度、支撑阻尼和间隙对转子在坠落过程中动力特性的影响。结果表明采用具有较大阻尼柔性结构的备用轴承能够显著地改善转子坠落在备用轴承上的瞬态动力特性,抑制转子在坠落过程中可能出现具有较大振动和冲击力的全间隙区的涡动运动,减小转子坠落对备用轴承寿命和可靠性的影响。柔性结构备用轴承的支撑阻尼越大,支撑刚度越小,间隙越大,转子坠落后出现全间隙区涡动运动的可能性越小。 相似文献
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The following elaboration discusses the analytically complete layout of a self-acting gas-lubricated high-speed conically shaped spiral-groove bearing as well as suggestions for practical realization. The simple conically shaped bearing is separated into two conical main bearings, which are situated at the ends of the cone-stump. Both have an identical angle size, but otherwise differ with regard to their bearing geometries and bearing gap sizes. The isotropic layout of the two bearings in radial direction, i.e. the determination of the bearing geometries for the same load angle, the same load capacity and the same stiffness at the same nominal operating conditions, is determined analytically in an iterative way and has the goal of providing dynamically benign behavior. The radial expansion of the rotor which occurs at the nominal rotation, and therefore the occurrence of distortions of the bearing gaps due to enormous centrifugal forces that affect the rotor masses, is rendered ineffective by means of a centrifugal force invariant inner outline of the rotor. For this purpose, the outer contour of the rotor is designed in such a manner that the conically shaped inner contour expands congruently to itself and therefore causes a parallel increase in the bearing gap. The autonomous regulation of the bearing following the gap increase subject to the decrease in load capacity as a result of the decrease of the expanded rotor to the nominal bearing gap sizes restores the nominal state independent of the rotor speed. The half-frequency whirl which is dependent on natural frequencies and detrimental to self-acting, gas-lubricated bearings requires an investigation of the dynamic behavior of the bearing system. It will be shown that natural frequencies will be reached while passing through the turning frequency range. However, the suspension of the “rotor–stator” system in defined additional stiffnesses will show that the natural frequencies of the original system can be displaced upwards so that the turning frequency will no longer reach a natural frequency at any operating point. This prevents the occurrence of the half-frequency whirl. The realization of the described bearing system is supported by suggestions for a non-self-acting start-up assistance at low rotation speeds as well as by suggestions for actuation, pre-stressing, sensor and measurement devices as well as system regulation. It lays the foundation for high-speed bearings in spindle construction, laser and dental technology as well as for precision gyroscopes. 相似文献
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非稳态油膜力作用下非线性刚度转子系统的碰摩故障分析 总被引:3,自引:0,他引:3
研究了在非稳态油膜力作用下非线性刚度转子系统发生碰摩时的振动问题。建立了非稳态油膜力作用的非线性刚度转子一轴承系统碰摩模型,应用数值分析的方法对其进行研究。通过Poincare截面图、轴心轨迹图、波形图和频谱图,直观地显示了系统在某些参数域中的运动状态。发现了由于油膜力作用出现油膜涡动和反向涡动现象以及倍周期分岔、概周期和混沌等复杂的动力学行为。数值分析结果为该类转子一轴承系统的设计和运行状态控制提供了理论参考。 相似文献
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Tae Jong Kim Kyung Tae Kim Sang-Moon Hwang No-Gill Park Shi-Bok Lee 《Journal of Mechanical Science and Technology》2002,16(12):1576-1582
Vibration of a BLDC motor is a coupled phenomenon between mechanical characteristics and magnetic origins which takes place
through the motor airgap. When relative misalignment of a rotor in the airgap is introduced during assembly, the dynamic characteristics
of the motor system are affected. The rotor-motor system used in a washing machine is modeled using FETM and magnetic forces
in a BLDC motor with radial rotor eccentricity are determined analytically. The transient whirl responses of a rotor system
supported on two roller bearings with relative misalignment in the motor airgap are investigated by considering mechanical
and magnetic coupling effects. Results show that rotor misalignment in the airgap considerably affects the vibration of the
rotor-motor system. 相似文献
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In this paper, recent results controling nonlinear systems with output tracking error constraints are applied to the design of new tracking controllers for magnetic bearings. The proposed controllers can force the rotor to track a bounded and sufficiently smooth refer-ence trajectory asymptotically and guarantee non-contactedness be-tween the rotor and the stator of the magnetic bearings. Simulation results are included to illustrate the effectiveness of the proposed con-trollers. 相似文献