共查询到18条相似文献,搜索用时 187 毫秒
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对基于电磁执行器的一种新型支承结构--电磁辅助支承的被动阻尼减振和主动阻尼减振进行比较.首先通过各自的数学模型分析其阻尼减振的不同机理,然后在一四自由度电磁辅助支承转子系统中进行验证,并取得较好的实验效果.通过比较可知,在被动阻尼控制中电磁执行器仅提供负的动刚度和随转速变化的动阻尼;而主动阻尼控制则可以根据需要提供正负刚度和固定或变化的阻尼;且在相同的静态励磁电流下,主动减振效果优于被动减振,但前者结构复杂,造价较高,而后者实施容易. 相似文献
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安装在移动载体上的电磁轴承-转子系统往往会受到来自其承载基础的振动激励干扰。对单自由度支承模型和多自由度转子模型在基础激励条件下的动力学响应进行比较分析,认为可以将基础激励引起的电磁轴承-转子系统定转子之间的相对运动等效为一个由基础加速度决定的强迫振动。提出一种基于基础加速度信号作为参考信号的自适应滤波器的电磁轴承-刚性转子系统基础激励响应抑制方法,并分析该方法抑制各种类型振动的有效范围,所需滤波器的阶数,以及滤波器自适应收敛的最佳权值。在电磁轴承-转子系统试验平台上进行试验,结果表明提出的控制方法对稳定的基础激励造成的转子振动响应能有效抑制,强制定转子间隙保持稳定,避免碰撞。 相似文献
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研究了转子在工作转速下实现在线自动平衡的方法。以电磁执行器作为施力装置,运用傅里叶分析和线性系统的叠加原理,对不停车的情况下转子不平衡振动的识别和抑制的算法进行了推导,并在一滚珠轴承支承的转子系统上进行了试验研究。结果证明该方法和装置能够使旋转工作频率下转子的不平衡振动大大减小。 相似文献
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多跨转子系统多频传递力变步长神经网络控制 总被引:1,自引:0,他引:1
转子在旋转过程中,转子上的各种激励力会通过轴承传递给基础,从而导致基础的振动.为了抑制多频传递力,提出一种基于跟踪滤波后轴颈位移和传递力误差信号的变步长神经网络算法.设计一种集电磁执行器与固定瓦滑动轴承于一体的混合支承结构,并建立其动力学模型.用有限元法建立多跨转子系统的动力学模型,分析传递力控制的基本原理,采用离散跟踪微分器和状态观测器分别解决位移信号夹杂白噪声不易微分和传感器与执行器不同位时执行器位置处轴颈位移的重构问题.提出一种能够抑制多跨转子系统多频传递力的变步长神经网络算法.以一个四轴承二跨转子系统的仿真模型为例进行仿真分析,对所提出的变步长神经网络算法抑制双跨转子系统传递力的有效性进行了验证.结果表明,变步长神经网络算法能够有效地抑制转子系统对基础的多频传递力. 相似文献
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电磁辅助支承恒压源与恒流源被动式减振之比较 总被引:1,自引:0,他引:1
对电磁辅助支承的两种被动减振类型(恒压型和恒流型)进行研究,建立了各自的数学模型,揭示了它们不同的减振机理:在恒压源被动减振控制情况下,电磁辅助支承中的电磁执行器不仅提供与转速无关的负的静态位移刚度,而且提供随转速变化的附加(正)刚度和(正)阻尼;而在恒流源被动减振控制下,线圈中的电流保持恒定, 电磁执行器仅提供不随转速变化的负的静态位移刚度。最后在一对称转子系统上进行了试验验证,并取得了较好的减振效果。 相似文献
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主动电磁轴承转子系统振动模态的分析研究 总被引:3,自引:0,他引:3
概要介绍了电磁轴承支承下多质点柔性转子振动模态计算分析方法 ,对一套低温制氧高速透平膨胀机的电磁轴承转子系统的振动模态进行了分析 ,阐述了电磁轴承转子系统振动模态与传统油膜轴承转子系统振动模态的不同之处 ,指出了振动模态分析对电磁轴承系统传感器安装位置设计的重要性 ,及传感器安装位置的设计原则。 相似文献
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基于遗传算法的多自由度非线性振动的模糊控制方法 总被引:2,自引:0,他引:2
由于非线性系统的复杂性,难以得到基于线性控制规律的有效控制方法。本文对于复杂的多自由度非线性振动系统提出了基于遗传传算法的主动模糊控制方法。 相似文献
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This article presents a nonlinear dynamic model for a cylindrical roller bearing–rotor system with interaction forces between the inner race, outer race, and roller. Roller–race contacts are modeled predicting nonlinear stiffness (Hertz contact theory) and nonlinear damping for a rotor–cylindrical roller bearing system. Here a shaft–rotor bearing system is modeled with 9 degrees of freedom with one defect on the inner race and one defect on the outer race for a case of combined localized defects. In the mathematical formulation, contacts between rolling elements and inner and outer races are considered as nonlinear springs and nonlinear damping is taken into consideration. Contact force calculations with nonlinearity are solved using the Newton-Raphson method for n unknown nonlinear simultaneous equation. The Newmark-β implicit integration technique coupled with the Newton-Raphson method is used to solve the differential equations. The results are obtained in the form of a time domain plot, frequency domain plot, and phase plot/Poincare map. The validity of the proposed model is compared with experimental results. A bifurcation graph of speed versus peak amplitude predicts the behavior of the system. 相似文献
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Stability analysis of a rotor bearing system due to surface waviness and number of balls 总被引:3,自引:0,他引:3
In the paper, the stability analysis of a rigid rotor supported by ball bearings has been studied. In the analytical formulation, the contacts between balls and races are considered as nonlinear springs, whose stiffnesses are obtained by using Hertzian elastic contact deformation theory. The implicit type numerical integration technique Newmark-β with Newton–Raphson method is used to solve the nonlinear differential equations iteratively. The effects of surface waviness and the varying number of balls on stability of rotor bearing system are observed. All results presented in form of fast fourier transformations show that the vibration characteristics of the rotor and its bearings change, when the bearings operate in different regions of their nonlinear load deflection characteristics. From the analysis, it is implied that the number of balls and number of waves in the ball bearing are two important governing parameters affecting its dynamic behavior. 相似文献
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A novel nonlinear model of rotor/bearing/seal system based on the Hamilton principle is proposed for steam turbine systems in power plants. The Musznyska model and unsteady bearing oil-film force model were applied to describe the nonlinear steam excitation force and oil-film force. The Runge-Kutta method was used to solve the motion equation of the rotor/seal/bearing system. The dynamic characteristics of the rotor/bearing/seal system were analyzed with bifurcation diagrams, time-history diagrams, trajectory diagrams, Poincare maps and frequency spectrums. The numerical analysis indicates that the seal force and the oil-film force influence the nonlinear dynamic characteristics of the rotor system. With the increase of rotation speed, the rotor system exhibits rich forms of periodic, double-periodic, multi-periodic, quasi-periodic and chaotic motion. The combined impact of steam excitation force and bearing oil-film force may cause a severe vibration which seriously affects the safety and stability of the rotor. The presented model provides a theoretic foundation for further research on the ultra-supercritical steam turbines. 相似文献
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For the influence of rolling bearing radial clearance on the whole vibration in the aero-engine whole system, a real engine rotorbearing- casing whole model is established. The rotor and casing systems are modeled by means of FEM; the support systems are modeled by lumped-mass model; rolling bearing radial clearance and strong-nonlinearity of Hertz contact force at four different supports are considered. The coupled system response is obtained by the numerical integral method. The characteristics of the whole vibration response are analyzed. For rolling bearing at a typical support, the rotor, outer ring of rolling bearing and casing response characteristics at different rotating speeds are analyzed. The changing law of contact forces for each ball and the global contact forces at different speeds are analyzed. The influence of the radical clearance on the contact forces on the whole vibration is analyzed. The results show that the contact forces will be larger and the acceleration amplitude jumps obviously when the radial clearance is increased, and due to the variable stiffness of the rolling bearing, the natural frequency will appear when the stiffness changes fiercely, that is frequency-locked phenomenon. When the radical clearance is larger and the rotating speed is between two critical speeds, the rotor squeezes the outer ring now and then. Reducing the radical clearance can reduce the whole vibration and increase the rotor’s stability. 相似文献