共查询到13条相似文献,搜索用时 78 毫秒
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非线性振动系统的同宿轨道分叉、次谐分叉和混沌 总被引:1,自引:0,他引:1
本文首先利用 Melnikov 方法研究了在参数激励与强迫激励联合作用下具有 van der Pol 阻尼的非线性振动系统的同宿轨道分叉、次谐分叉和混沌,然后利用数值计算方法研究了这类系统的混沌运动。所得结果揭示了一些新的现象。 相似文献
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对非轨道面绳系卫星的研究揭示系统动力学特性、拓展应用维度,较对轨道面内系统的探究更有意义与价值。本文研究绳系卫星面外滚转的混沌行为。基于不可拉压刚性杆模型,考虑卫星刚体和系绳的质量及几何特性,引入大气阻尼、太阳光压对系统的面外摄动,导出无量纲动力学方程。利用Melnikov方法,解析得到受扰系统鞍点附近因异宿轨道破缺诱发面外滚转混沌的必要条件。数值给出系统参数混沌域,分析轨道参数、结构参数等对其的影响,并以具有混沌/概周期特性的面外滚转算例进行验证。 相似文献
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通过理论分析和数值试验,研究了由连续帐篷微分方程离散化所得新非光滑离散混沌系统在参数小于1时的动力学性质,设计了压缩反馈控制和非线性脉冲反馈控制两种混沌控制方案.结果表明:该系统在参数小于2时具有不同于倍周期分岔机制的混沌突发现象.设计的控制器能把该系统由混沌态稳定到1,2,4,5,6,8,10,12等周期态.控制器的可行性、有效性及鲁棒性通过数值试验得到证实. 相似文献
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催化氧化器是载人航天器中的微量污染净化装置的一个重要组成部分。提出了一种新型自整定模糊
控制器控制催化氧化器工作温度,它采用在线Bang唱bang方法获得系统特性,利用所提出的整定公式计算出模糊
控制器的输入输出因子,将这些比例因子与标准查寻表结合,实现了自整定模糊控制器的设计。 相似文献
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针对挠性航天器大角度姿态机动的振动抑制问题,提出了一种基于输出反馈滑模控制和输入成形振动抑制方法相结合的主动振动控制策略。输入形成器作为前馈控制器作用在反馈回路的前相通道,通过改变输入命令的作用形式,在保证参考模型(标称对象)完成指定的姿态机动的同时抑制掉对系统影响较大的挠性结构的振动;而对于闭环控制回路,考虑挠性结构模态不可测、模型参数具有不匹配不确定性以及外干扰力矩的作用,在输出反馈滑模控制的基础上,给出了仅利用输出信息的滑模控制器设计方法,保证跟踪参考模型的输出以获得要求的闭环系统的性能。将该方法应用于单轴挠性航天器的大角度rest—to—rest(静止到静止)姿态机动控制进行了仿真研究,结果表明,所提出的方法是可行而有效的。 相似文献
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提出了一个新混沌系统,通过Matlab对该系统进行了分岔图、Lyapunov指数、相图等仿真分析,证实了在选定特定参数下,该系统为混沌系统。随着参数的改变,该系统会出现周期–倍周期–混沌–周期–倍周期–混沌交替现象,具有较复杂的动力学特性及对初值的敏感性,通过Multisim电路仿真证实了该系统的物理可实现性。针对提出的新混沌系统,设计了错位投影同步控制器,从理论上证实了在同步控制器的作用下该系统与Chen混沌系统达到了同步,通过Matlab仿真证实了同步控制器的有效性。最后,在同步控制器作用下实现了新混沌系统和Chen混沌系统的数字加密传输。 相似文献
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LUOKai 《国际设备工程与管理》2005,10(2):82-88
Stability is a key problem that means whether a high rate rotor-active magnetic bearings system works reliably or not. Aiming at a bearings system described with nonlinear equations, this paper built a linear model according to the system behavior. Considering realization of the control system and behavior of a high rate rotor system (magnetic force is far smaller than input force produced by mass eccentricity) this paper proposes a design method of variable parameters PD control algorithm that can be used universally. The control system was simplified and a mass of adjusting work of control parameters was reduced. Analysis and simulation indicated that the bearings system could get a wider stable region of harmonic motion, and proved that the algorithm is robust and advanced. The control system can be realized because the winding electric currents are positive. The method is convenient for operation and can easily be used for engineering practice. 相似文献
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D. Palaniappan 《Journal of Superconductivity and Novel Magnetism》2009,22(5):471-477
The calculation of the magnetostatic potential and levitation force due to a point magnetic dipole placed in front of a superconducting
sphere in the Meissner state is readdressed. Closed-form analytical expression for the scalar potential function that yields
the image system for an arbitrarily oriented magnetic dipole located in the vicinity of a superconducting sphere is given.
Analytic expression for the lifting or levitation force acting on the sphere is extracted from the solution for a general
dipole. A special case of our expression where the initial magnetic dipole makes an angle with the z-axis is derived. Our expression for the force in this particular case shows that a recently obtained result (J. Supercond.
Nov. Magn. 21:93–96, 2008) for an arbitrary dipole is incorrect. A brief discussion of another erroneous result (J. Supercond. Nov. Magn. 15:257–262,
2002) for a transverse/tangential dipole–sphere configuration, corrected elsewhere recently, is reproduced. Correct expressions
for the interaction energy with some limiting cases are also provided. The result derived here demonstrates that the value
of the levitation force for a dipole that makes an angle with z-axis lies between the values for a radial dipole–sphere and transverse dipole–sphere configurations providing upper and lower
bounds. It is found that for a magnetic dipole making an angle with z-axis, there exits a second force component along the negative y-direction, which influences a couple acting on the superconducting sphere. It is also shown that the couple is proportional
to the second force component and that both the couple and second force components vanish for a radial dipole–sphere and transverse
dipole–sphere configurations, respectively. These results appear to be new and have not had received due attention in the
context of superconductivity. 相似文献