共查询到19条相似文献,搜索用时 109 毫秒
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在混沌有益时,有目的地产生混沌已经成为混沌学研究的热点问题,本文提出直接延迟反馈实现混沌的反控制,在非混沌系统中产生了混沌.该方法与间接延迟反馈控制方法相比,控制更加简单,更易于实现.该方法与Pyragas提出的延迟反馈混沌控制方法的控制器结构相同,因此,这种直接延迟反馈控制方法可以在需要混沌时产生混沌,不需要混沌时控制混沌,实现混沌控制和反控制的统一,为设计者提供最大的灵活性.针对参数处于非混沌区的Chen系统和Lorenz系统的仿真结果表明了该混沌反控制方法的有效性.
关键词:
混沌
反控制
直接延迟反馈 相似文献
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提出了外腔延时反馈半导体激光器法拉第效应控制下的新激光系统, 构造出两种类型结构光路, 建立了法拉第效应控制下的延时负反馈、延时正反馈激光动力学物理模型, 研究了激光混沌控制与反控制等. 利用法拉第效应原理及磁致旋光性和系统特点, 调节控制光路中的光旋转角度和光延时间可实现双参数控制激光器, 控制激光到双周期、三周期及多周期, 使激光产生拍动等现象, 反控制激光周期到混沌等. 发现了以磁致旋光角分布的激光混沌控制与反控制区域. 并研究了激光混沌控制与周期控制的动态情况, 演示讨论了激光态的转化演变过程等. 相似文献
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提出了基于稳定性准则的延迟非线性反馈控制混沌的方法,即SC延迟非线性反馈控制法. 通过对混沌系统的适当分离,得到一个特殊的非线性函数,并利用混沌输出信号与其延迟信号的非线性函数的差,构造了连续反馈输入干扰,以控制混沌轨到某一期望的不稳周期轨上. 该方法继承了延迟反馈控制方法的优点,实现了自-控制过程. 另外由于该方法基于线性系统的稳定性准则,保证了控制的有效性. 控制过程可随时开始,具有简便、灵活性. 给出耦合Duffing振子的例子,数值模拟结果显示了SC延迟反馈方法控制的有效性.
关键词:
稳定性准则
混沌控制
延迟反馈
干扰 相似文献
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This paper undertakes a nonlinear analysis of a model for a maglev system with time-delayed feedback. Using linear analysis, we determine constraints on the feedback control gains and the time delay which ensure stability of the maglev system. We then show that a Hopf bifurcation occurs at the linear stability boundary. To gain insight into the periodic motion which arises from the Hopf bifurcation, we use the method of multiple scales on the nonlinear model. This analysis shows that for practical operating ranges, the maglev system undergoes both subcritical and supercritical bifurcations, which give rise to unstable and stable limit cycles respectively. Numerical simulations confirm the theoretical results and indicate that unstable limit cycles may coexist with the stable equilibrium state. This means that large enough perturbations may cause instability in the system even if the feedback gains are such that the linear theory predicts that the equilibrium state is stable. 相似文献
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The stabilizing effects of local enrichment are revisited. Diffusively coupled host-parasitoid and predator-prey metapopulations are shown to admit a stable fixed point, limit cycle or stable torus with a rich bifurcation structure. A linear toy model that yields many of the basic qualitative features of this system is presented. The further nonlinear complications are analyzed in the framework of the marginally stable Lotka-Volterra model, and the continuous time analog of the unstable, host-parasitoid Nicholson-Bailey model. The dependence of the results on the migration rate and level of spatial variations is examined, and the possibility of “nonlocal” effect of enrichment, where local enrichment induces stable oscillations at a distance, is studied. A simple method for basic estimation of the relative importance of this effect in experimental systems is presented and exemplified. 相似文献
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随着我国现代化进程的不断加快,航天航空技术标准越来越高,对于航空发动机运转工况的鲁棒性和适应性提出了更高的要求。传统的航空发动机变增益设计步骤繁琐,不能将发动机置于整个航空器的运转去考虑设计,使发动机变增益缺乏相应的稳定性和适应性,易出现系统问题。为此,提出一般基于LPV的航空发动机鲁棒变增益控制系统,依据航空发动机结构参数,考虑到航空器在空中负载特性,计算出新的约束极点 模糊变增益,在航空器发动机工作范围连续增益,避免了传统增益切换情况,在转速控制上确定误差等因素,将非线性控制设计分解为多个线性子问题,使航空器控制系统能够沿着LPV参数轨迹保持良好的运转,保持稳定性能。仿真实验证明,提出的基于LPV的航空发动机鲁棒变增益控制系统控制效果优于传统方法,在航空器发动机转速改变时,控制精度能够满足要求 ,改变航空器负载时,有效对目标进行变增益控制。提出的控制方法对航空发动机鲁棒变增益控制问题提供了新的解决办法,具有较大应用价值。 相似文献
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L.J. Song J. Ma D. Yan X.G. Wang 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2012,66(8):1-5
We introduce a method of quantum tomography for a continuous variable system in position and momentum space. We consider a single two-level probe interacting with a quantum harmonic oscillator by means of a class of Hamiltonians, linear in position and momentum variables, during a tunable time span. We study two cases: the reconstruction of the wavefunctions of pure states and the direct measurement of the density matrix of mixed states. We show that our method can be applied to several physical systems where high quantum control can be experimentally achieved. 相似文献
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N. S. ?eng?r Y. ?ak?r C. Güzeli? F. Pekergin ?. Morgül 《ARI - An International Journal for Physical and Engineering Sciences》1999,51(4):268-276
Several formulations and methods used in solving an NP-hard discrete optimization problem, maximum clique, are considered in a dynamical system perspective proposing continuous methods to the problem. A compact form for a saturated linear dynamical network, recently developed for obtaining approximations to maximum clique, is given so its relation to the classical gradient projection method of constrained optimization becomes more visible. Using this form, gradient-like dynamical systems as continuous methods for finding the maximum clique are discussed. To show the one to one correspondence between the stable equilibria of the saturated linear dynamical network and the minima of objective function related to the optimization problem, La Salle's invariance principle has been extended to the systems with a discontinuous right-hand side. In order to show the efficiency of the continuous methods simulation results are given comparing saturated the linear dynamical network, the continuous Hopfield network, the cellular neural networks and relaxation labelling networks. It is concluded that the quadratic programming formulation of the maximum clique problem provides a framework suitable to be incorporated with the continuous relaxation of binary optimization variables and hence allowing the use of gradient-like continuous systems which have been observed to be quite efficient for minimizing quadratic costs. 相似文献
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Woo-Pyo Hong 《Optics Communications》2008,281(24):6112-6119
We study the properties of the coherent structures induced by the modulational instability (MI) of the two linearly coupled complex Ginzburg-Landau equations with both cubic and quintic terms, which in nonlinear optics can model ring lasers based on dual-core fibers. We obtain new stationary solutions different from the previous result and the analytic gain formula as function of the linear coupling constant and the model parameters. The fact that the system can be modulationally unstable for the vast region of the parameters space is demonstrated. The effects of the linear coupling constant on the evolution of a continuous wave under the MI are numerically investigated in the presence of the linear loss or gain. It is found that doubly asymmetric stable solitary pulses and stable breathers can be formed from the perturbed continuous waves state by the MI. The conditions for generating the periodic stable solitary pulses and fronts by the MI are identified by varying the linear coupling constant. 相似文献