利用非线性函数控制的混沌异结构同步

研究了利用非线性函数控制的混沌异结构同步问题.基于Lyapunov稳定性理论,设计了非线性控制函数,使得同步误差系统的Lyapunov函数的形式为V(e)=eTPe(P为正定矩阵),根据数学公式推导,理论证明了该方法可以实现不同混沌系统之间的异结构同步.数值模拟进一步验证了所提出方案的有效性.     

Stabilizing unstable equilibria of chaotic systems from a State observer approach

In this paper, a simple control method is proposed for stabilizing unstable equilibria of two typical classes of chaotic systems. For piecewise-linear chaotic systems, such as Chua's circuit, the control parameters can be selected via the pole placement technique from the linear control theory. For general nonlinear chaotic systems with continuously differentiable nonlinearities, particularly polynomial chaotic systems such as the Ro/spl uml/ssler system, Lorenz system, Chen's system, and the modified Chua's circuit with cubic nonlinearity, the control parameters can be chosen according to the pole placement technique and some additional theories of nonlinear ordinary differential equations. The criteria for the design of the control parameters are also investigated. This method is demonstrated to be highly robust against system parametric variations. To verify the effectiveness of the method, it is applied to both the original and the modified chaotic Chua's circuits, where satisfactory control performance is observed in simulations.     

异结构时滞不确定混沌系统的同步/反同步控制及其应用

为了研究具有不同参数的两个不确定时滞混沌系统的同步与反同步控制及在保密通信中的应用,首先对反馈时滞Lorenz混沌系统的系统参数进行重新设计,并引入正弦函数扰动,获得两个具有不同吸引子的时滞混沌系统.采用主动控制方法实现了具有不同参数的时滞混沌系统的同步及反同步控制.为了实现保密通信,将明文信号参与混沌运算,并结合混沌...     

混沌动力学系统的神经网络学习控制研究

针对混沌动力学系统建模困难，控制不易实现，存在干扰等特点，在附加动量法的自适应BP网络的基础上，研究了混沌动力学系统的学习控制策略。构建了混沌动力学系统的NN模型和NN控制器，对混沌系统在学习的同时施加控制，仿真实验结果表明，该控制策略具有鲁棒性强，有良好的适应性，网络参数训练时间短等优点。     

一类混沌系统的动态输出反馈控制

为了对一类混沌系统实施控制,提出了利碍新的控制器来控制混沌系统。以往的混沌控制方法只针对个别特殊的混沌系统,而利用动态输出反馈的方法能控制一类混沌系统,这方面的工作以前也曾有过。利用李雅普诺夫稳定理论,结合线性矩阵不等式优化方法,分析了系统的稳定性。数值仿真也表明了所提出的控制策略的有效性。     

基于Lorenz系统切换混沌同步的保密通讯

该文提出利用Lorenz系统切换混沌同步实施保密通讯的方法。构建了有一定关联的两个Lorenz混沌系统,并通过选择器在系统间随机切换;用同一种控制方法既能实现不同Lorenz系统的混沌同步,又能实现相同Lorenz系统的混沌同步;发送系统可以在Lorenz混沌系统间随机转换,传输信道中混沌调制信号也随之不断变化;接收系统将混沌调制信号解调后,即可获取有用信号。由于发送系统的可选择性,导致保密信号的多样性和随机性,因此该保密通讯方法具有更好的保密性能。     

一种可完全线性化的不同类型混沌系统同步方法

讨论可完全线性化的不同类型混沌系统之间的同步问题.根据滑模控制原理求取混沌同步控制形式,利用扩张状态观测器对系统信息进行渐进估计,把复杂的滑模控制策略变为可实现的控制方式,以此实现具有不确定性混沌系统的同步.以Duffing和Vander Pol系统为例进行仿真,效果良好.     

一种基于混沌蚂蚁群算法的系统参数辨识方法

提出了一种基于混沌蚂蚁群算法的控制系统辨识方法,这种方法在给定控制系统数学模型的条件下,将控制系统的参数辨识问题转化为参数的寻优问题,之后利用混沌蚂蚁群算法的全局优化搜索能力对问题进行求解.以典型控制系统为例进行了计算机仿真,实验结果表明,使用混沌蚂蚁群算法可以得到很好的参数估计结果.     

Global Asymptotical Synchronization of Chaotic Lur'e Systems Using Sampled Data: A Linear Matrix Inequality Approach

Sampled-data feedback control for master-slave synchronization schemes that consist of identical chaotic Lur'e systems is studied. Sufficient conditions for global asymptotic synchronization of such chaotic Lur'e systems are obtained using the free-weighting matrix approach and expressed in terms of linear matrix inequalities (LMIs). With the help of the LMI solvers, the sampled-data feedback control law can easily be obtained to globally asymptotically synchronize Lur'e chaotic systems. The effectiveness of the proposed method is finally illustrated via numerical simulations of chaotic Chua's circuits.     

一种混沌系统的控制方法

系统的李雅普诺夫指数可用作判断系统是否混沌的依据，通过改变系统李雅普诺夫指数改变系统的运动状态，达到控制混沌系统的目的，理论分析和仿真实验结果均表明，该控制策略是有效的，可以实现系统的快速稳定。     

Adaptive synchronization of Chen chaotic system with uncertain parameters

By the control method independent of system parameters, synchronization of two Chen chaotic systems with identical, but uncertain parameters is discussed in this article. Based on Lyapunov’s theorem, an adaptive controller and the parameters estimate update law are derived to make the solution of the error dynamical equation converge at the point E(0, 0, 0) with a quick speed, that is, the states of two Chen chaotic systems can be asymptotically synchronized. Numerical simulations verify the effectiveness and the adaptivity to the variation of Chen system parameters.     

基于线性状态反馈方法的Nadolschi混沌系统同步

研究了一类新型混沌系统——Nadolschi系统的同步控制问题。首先为响应系统设计一个多变量线性状态反馈控制器,进而将Nadolschi系统的同步控制问题转化为误差系统零平衡点的镇定问题。然后,根据Lyapunov稳定性理论,得出使Nadolschi混沌系统达到渐近同步的充分条件。仿真结果验证了所提方法的有效性,所设计的控制器具用结构简单,易于实现等优点。     

单参数统一混沌系统的自适应控制同步

研究了单参数统一混沌系统的同步问题,提出了参数自适应控制同步方法;通过构造适当的控制函数和设计参数的自适应控制律,实现了两个不同参数的统一混沌系统的同步;根据Lyapunov稳定性定理,导出了两不同参数混沌系统能实现同步的充分条件,无论驱动系统处于何种状态,该方法都可使响应系统按照驱动系统给定的轨道演化。数值仿真表明了该方法的有效性。     

Adaptive Fuzzy Control of Nonlinear in Parameters Uncertain Chaotic Systems Using Improved Speed Gradient Method

This paper presents an adaptive fuzzy controller for Nonlinear in Parameters (NLP) chaotic systems with parametric uncertainties. In the proposed controller, the unknown parameters are estimated by the novel Improved Speed Gradient (ISG) method, which is a modification of Speed Gradient (SG) algorithm. ISG employs the Lagrangian of two suitable objective functionals for on-line estimation of system parameters. The most significant advantage of ISG is that it is applicable to NLP systems and it results in a faster rate of convergence for the estimated parameters than the SG method. Estimated parameters are used to design the fuzzy controller and to calculate the Lyapunov exponents of the chaotic system adaptively. Furthermore, established on the well-known Takagi–Sugeno (T-S) fuzzy model, a LMI (Linear Matrix Inequality)-based fuzzy controller is designed and is tuned using estimated parameters and Lyapunov exponents. Throughout the controller design procedure, several important issues in fuzzy control theory including relaxed stability analysis, control input performance specifications, and optimality are taken into account. Combination of ISG parameter estimation method and T-S-based fuzzy controller yields an adaptive fuzzy controller capable to suppress uncertainties in parameters and initial states of NLP chaotic systems. Finally, simulation results are provided to show the effectiveness of the ISG and adaptive fuzzy controller on chaotic Lorenz system and Duffing oscillator.     

基于小波变换的超混沌系统同步

提出了一种基于反馈控制与小波变换相结合的超混沌系统同步方法。在发送端 ,将系统的部分信号进行小波变换去掉细节信息后发送 ,在接收端重构出低频信号 ,将其与接收端信号的差进行离散反馈 ,可以使两个结构相同的超混沌系统达到混沌同步。同时 ,参数失配和噪声对同步的影响被讨论。应用本同步方法可将发送信号压缩后传送 ,节约系统资源 ;滤去发送信号的高频成分 ,减小干扰对同步信号中的影响。文中给出了仿真验证结果。     

基于联合混沌系统的保密通信方法研究

提出了利用离散混沌系统联合加密来实现保密通信的方法。引用著名的Henon和Lorenz混沌系统作为仿真实验证明了其可行性，混沌系统均采用backstepping和dead-beat同步设计方案，以快速达到同步，理论分析证明，此种方法不仅是可行的，且与非联合混沌系数相比，加强了保密性。混沌屏蔽技术仿真结果也证明，该系统不仅实现简单，容易控制，而且增强了整个系统的保密性能。     

A new chaotic secure communication system

The paper proposes a digital chaotic secure communication by introducing a magnifying glass concept, which is used to enlarge and observe minor parameter mismatch so as to increase the sensitivity of the system. The encryption method is based on a one-time pad encryption scheme, where the random key sequence is replaced by a chaotic sequence generated via a Chua's circuit. We make use of an impulsive control strategy to synchronize two identical chaotic systems embedded in the encryptor and the decryptor, respectively. The lengths of impulsive intervals are piecewise constant and, as a result, the security of the system is further improved. Moreover, with the given parameters of the chaotic system and the impulsive control law, an estimate of the synchronization time is derived. The proposed cryptosystem is shown to be very sensitive to parameter mismatch and hence the security of the chaotic secure communication system is greatly enhanced.     

滑模控制策略在具有不确定性的混沌系统同步中的应用

根据滑模控制原理求取混沌同步控制形式，利用扩张状态观测器对系统信息进行渐进估计，得到物理可实现的同步控制策略，以此实现具有不确定性混沌系统的同步。以Duffing和VanderPol系统为例进行仿真，效果良好。     

基于变参数的仓储管理过程混沌控制研究

针对仓储管理过程中的一类多参数混沌情况，采用微分动力学原理，提出基于变参数结构的反馈控制方法，解决了多参数的控制问题，比OGY方法简单，实用、并具有稳定控制的能力。     

基于反正切的网格混沌吸引子及其保密通信

提出了一种用处处光滑的反正切函数序列生成多维多涡卷网格混沌吸引子的方法,可以生成一维n涡卷、二维n×m网格多涡卷和三维n×m×l网格多涡卷混沌吸引子。平衡点分析、数值仿真、Lyapunov指数谱、分岔图和Poincaré映像都表明系统是混沌的。用简单的线性反馈控制实现了同结构网格多涡卷混沌系统之间的同步,可应用于保密通信。简单的理论分析和数值仿真证明了该方法的有效性。