Lag projective synchronization in fractional-order chaotic (hyperchaotic) systems

In this Letter, a new lag projective synchronization for fractional-order chaotic (hyperchaotic) systems is proposed, which includes complete synchronization, anti-synchronization, lag synchronization, generalized projective synchronization. It is shown that the slave system synchronizes the past state of the driver up to a scaling factor. A suitable controller for achieving the lag projective synchronization is designed based on the stability theory of linear fractional-order systems and the pole placement technique. Two examples are given to illustrate effectiveness of the scheme, in which the lag projective synchronizations between fractional-order chaotic Rössler system and fractional-order chaotic Lü system, between fractional-order hyperchaotic Lorenz system and fractional-order hyperchaotic Chen system, respectively, are successfully achieved. Corresponding numerical simulations are also given to verify the analytical results.     

A simple method to simultaneously achieve synchronization andanti-synchronization in chaotic systems

In this paper, a novel adaptive control approach is presented to simultaneously achieve synchronization and anti-synchronization in partially linear chaotic systems. Through appropriately separating state vectors of such systems, synchronization and anti-synchronization could be simultaneously realized in different subspaces, which may be strictly proven theoretically. Simulation results for a Lorenz chaotic system and a new hyper-chaotic system are provided to illustrate the effectiveness of the proposed method. Finally, a new secure communication scheme based on such a synchronization phenomenon of the hyper-chaotic system is demonstrated. Numerical results show success in transmitting a periodic signal with high security.     

多涡卷混沌系统的广义同步控制

基于反步自适应方法,提出了一种在初值不同以及驱动系统参数未知的情况下,保持驱动和响应两多涡卷混沌系统同步的控制律设计方法.该方法所设计的控制律能够同时适用于两混沌系统的完全同步、反同步和一类非线性广义同步,具有较高的实用价值.仿真结果表明了所设计控制律的有效性. 关键词： 多涡卷混沌 广义同步 反步 自适应     

不同结构混沌系统的自适应同步和反同步

针对不同结构混沌系统的同步与反同步问题进行了研究.在系统参数已知时,采用主动控制法实现混沌系统的同步与反同步,并将主动控制器的设计方法进行了推广.在参数未知时,基于Lyapunov稳定性理论和自适应控制方法,给出了自适应控制器和参数自适应律,实现了参数均未知且结构不同的驱动系统和响应系统的同步与反同步.在控制器的设计过程中,将驱动系统和响应系统进行互换,讨论了互换前后的控制器和自适应律之间的关系.数值仿真结果说明了所提出设计方法的有效性. 关键词： 混沌同步 反同步 主动控制法 自适应控制法     

Hybrid synchronization of hyperchaotic Lu system

In this paper, we study the hybrid synchronization between two identical hyperchaotic Lu systems. Hybrid synchronization of hyperchaotic Lu system is achieved through synchronization of two pairs of states and anti-synchronization of the other two pairs of states. Active controls are designed to achieve hybrid synchronization between drive and response systems using the sum and difference of relevant variables of the chaotic systems. Numerical simulations are presented to evaluate the analysis and effectiveness of the controllers.     

Synchronization of indirectly coupled Lorenz oscillators: An experimental study

The dynamics of indirectly coupled Lorenz circuits is investigated experimentally. The in-phase and anti-phase synchronization of indirectly coupled chaotic oscillators reported in Phys. Rev. E 81, 046216 (2010) is verified by physical experiments with electronic circuits. Two chaotic systems coupled through a common dynamic environment shows the verity of synchronization behaviours such as anti-phase synchronization, in-phase synchronization, identical synchronization, anti-synchronization, etc.     

Dynamical analysis of a new fractional-order Rabinovich system and its fractional matrix projective synchronization

This paper constructs a new physical system, i.e., the fractional-order Rabinovich system, and investigates its stability, chaotic behaviors, chaotic control and matrix projective synchronization. Firstly, two Lemmas of the new system's stability at three equilibrium points are given and proved. Next, the largest Lyapunov exponent, the corresponding bifurcation diagram and the chaotic behaviors are studied. Then, the linear and nonlinear feedback controllers are designed to realize the system's local asymptotical stability and the global asymptotical stability, respectively. It's particularly significant that, the fractional matrix projective synchronization between two Rabinovich systems is achieved and two kinds of proofs are provided for Theorem 4.1. Especially, under certain degenerative conditions, the fractional matrix projective synchronization can be reduced to the complete synchronization, anti-synchronization, projective synchronization and modified projective synchronization of the fractional-order Rabinovich systems. Finally, all the theoretical analysis is verified by numerical simulation.     

基于改进克隆选择算法的统一混沌系统同步控制与参数辨识

提出一种改进的克隆选择算法用于解决混沌系统的参数辨识问题.该算法利用抗体的高频变异和受体编辑两种机制有效平衡算法的全局探索与局部开发，并引入向精英抗体学习策略进一步提高算法的收敛质量.对10个优化问题的实验表明：所提出算法在求解精度、收敛速度以及稳定性方面具有更好的性能.以参数未知统一混沌系统的同步控制为研究对象，合理设计同步控制器，并对同步系统的稳定性进行理论分析.通过对同步比例因子的设置，实现统一混沌系统的完全同步、反同步、投影同步等多种同步方式.仿真实验结果表明该方法能够实现对未知系统参数的精确辨识以及驱动-响应系统的有效同步控制，验证了所提方法的可行性与有效性.     

混沌时滞神经网络系统的反同步

利用状态观测器方法研究了一类带时滞的混沌神经网络系统的反同步问题.与应用于其他混沌系统的反同步方法相比,提出的方法更为简便,并且利用极点配置技术,只要通过调整特征值来实现反同步速率的快慢.最后,给出了数值例子和计算机仿真结果来验证该方案的有效性. 关键词： 混沌神经网络 状态观测器 极点配置技术 反同步     

基于状态观测器的一类混沌系统的反同步

基于状态观测器方法和极点配置技术，设计出一种反同步方法，使得一类混沌系统达到了反同步.与其他反同步方法相比，所设计的方法更为简便，并且达到反同步的时间短.数值模拟验证了所提方案的有效性. 关键词： 状态观测器 极点配置技术 反同步     

对称非线性耦合混沌系统的同步

研究两个对称非线性耦合混沌系统的同步问题.通过对系统线性项与非线性项的适当分离， 构造一个特殊的非线性耦合项，发现在耦合强度α＝05附近的某一区域里存在稳定的 混沌同步现象.提供判断同步误差稳定性的方程，利用线性系统的稳定性分析准则和条件Lya punov指数来检验同步状态的稳定性.新方法适用于连续时间系统的混沌同步，也适用于具有 两个（或多于两个）正Lyapunov指数的超混沌系统.以Lorenz系统，超混沌Rssler 系统作 为算例，数值模拟结果证实所提新方法的有效性. 关键词： 混沌 同步 非线性耦合 稳定性准则 超混沌     

超混沌R?ssler系统构成的星形网络的混沌同步

通过对超混沌系统线性项与非线性项的适当分离配置，构造一个特殊的非线性耦合函数作为单元之间的耦合函数，提出非线性非对称耦合混沌同步方法，研究超混沌Rssler系统单元按照星形连接形式组成网络的同步问题.发现耦合强度在某一区域里存在着稳定的混沌同步现象.分析并讨论了不同参数在耦合过程中对混沌同步过程及其稳定性的影响.数值模拟结果证实该方法的有效性. 关键词： 超混沌同步 非线性耦合 R ssler系统 星形网络     

Global Synchronization & Anti-Synchronization in N-Coupled Map Lattices

By considering a symmetric N-dimensional map which possesses invariant measure in its diagonal and anti-diagonal invariant sub-manifolds, we have been able to propose an N-coupled map which possesses invariant measure in synchronized or anti-synchronized states. Then chaotic synchronization and anti-synchronization are investigated in the introduced model. We have calculated Kolmogrov–Sinai entropy and Lyapunov exponent as another tool to study the stability of N-coupled map in synchronized and anti-synchronization states.     

Anti-synchronization of chaotic oscillators

We have observed anti-synchronization phenomena in coupled identical chaotic oscillators. Anti-synchronization can be characterized by the vanishing of the sum of relevant variables. We have qualitatively analyzed its base mechanism by using the dynamics of the difference and the sum of the relevant variables in coupled chaotic oscillators. Near the threshold of the synchronization and anti-synchronization transition, we have obtained the novel characteristic relation.     

单模激光Lorenz系统反同步控制研究

提出了一种实现异结构混沌系统反同步控制的方法。根据Lyapunov 稳定性理论给出控制器的结构。以单模激光Lorenz系统和Rossler系统为例,验证了这种控制器的有效性。进一步研究了不确定混沌系统的反同步,并以不确定单模激光Lorenz系统和Rossler系统为例,实现了混沌反同步控制,同时系统中不确定参数得到识别。仿真模拟结果验证了这种方法的有效性。设计的反同步控制方法可用于任意混沌系统,具有一定的普适性。     

基于混沌粒子群优化算法的异结构混沌反同步自抗扰控制

针对一类连续时间异结构混沌系统, 利用自抗扰控制很强的鲁棒性, 提出了一种异结构混沌系统反同步的自抗扰控制策略.针对所设计的自抗扰控制器参数较多, 难以整定的问题, 提出了应用混沌粒子群优化算法对控制器进行参数寻优设计. 以Lorenz系统和Chua系统两个异结构混沌系统为例进行仿真验证, 由仿真结果可知, 该方法可以实现异结构混沌系统较快的反同步控制, 且具有很强的抗干扰能力. 关键词： 异结构混沌系统反同步 自抗扰控制器 混沌粒子群优化算法 参数寻优     

Reduced-order anti-synchronization of the projections of the fractional order hyperchaotic and chaotic systems

The article aims to study the reduced-order anti-synchronization between projections of fractional order hyperchaotic and chaotic systems using active control method. The technique is successfully applied for the pair of systems viz., fractional order hyperchaotic Lorenz system and fractional order chaotic Genesio-Tesi system. The sufficient conditions for achieving anti-synchronization between these two systems are derived via the Laplace transformation theory. The fractional derivative is described in Caputo sense. Applying the fractional calculus theory and computer simulation technique, it is found that hyperchaos and chaos exists in the fractional order Lorenz system and fractional order Genesio-Tesi system with order less than 4 and 3 respectively. The lowest fractional orders of hyperchaotic Lorenz system and chaotic Genesio-Tesi system are 3.92 and 2.79 respectively. Numerical simulation results which are carried out using Adams-Bashforth-Moulton method, shows that the method is reliable and effective for reduced order anti-synchronization.     

A simple adaptive controller for chaos and hyperchaos synchronization

A novel and simple adaptive feedback controller is proposed for chaos and hyperchaos synchronization. In comparison with previous methods, the present control scheme is not only simple but employs only one control strength, converges very fast and also suitable for a large class of chaotic and hyperchaotic systems. In addition, the synchronization is efficient in the presence of noise. Numerical simulations are used to validate and demonstrate the effectiveness of the method.     

Synchronization and anti-synchronization of chaos in an extended Bonhöffer–van der Pol oscillator using active control

In this paper, we investigate the complete synchronization and anti-synchronization (AS) of double-scroll chaotic attractor exhibited by an extended Bonhöffer–van der Pol (BVP) oscillator, using active control technique. In both synchronization schemes, the oscillators show good transient performance; while the AS state is further shown to correspond with complete inverse synchronization. Numerical simulations are also presented to verify the theoretical results.     

Mixed synchronization in chaotic oscillators using scalar coupling

We report experimental evidence of mixed synchronization in two unidirectionally coupled chaotic oscillators using a scalar coupling. In this synchronization regime, some of the state variables may be in complete synchronization while others may be in anti-synchronization state. We extended the theory by using an adaptive controller with an updating law based on Lyapunov function stability to include parameter fluctuation. Using the scheme, we implemented a cryptographic encoding for digital signal through parameter modulation.