具有噪声扰动的统一混沌系统的同步控制

研究了一类具有噪声扰动的统一混沌系统的同步控制问题。基于滑模变结构控制理论,提出了利用不确定性观测器估计扰动噪声,用噪声的观测值来设计控制器的新方法,而且适当选取观测器反馈增益可以使观测误差充分的小,从而可得到几乎没有受到扰动时的控制效果。和常规滑模变结构控制方法相比,所设计的控制器既能有效地抑制抖振,又能降低控制器参数设计的保守性。最后,基于Matlab 6.5软件对Lorenz混沌系统进行分析和数值模拟,验证了该滑模控制方法在混沌同步中的优良性能。     

Observer Based Projective Synchronization Method for a Class of Chaotic System-Part I: Linear Synchronization Subsystem

In this three-part paper, an observer based projective synchronization method for a class of chaotic system is proposed. At the transmitter, a general observer is used to create the scalar signal for synchronizing. In this part, the structure of the projective synchronization method is presented. And the condition of projection synchronization is theoretically analyzed when the synchronization subsystem is linear.     

对一类具有随机扰动的混沌系统同步的新方法

本文基于工程上广为应用的状态观测器思想,在随机扰动存在的情况下,对一类非线性反馈混沌系统成功地实现了同步.且在扰动很大时,系统仍能保持良好的同步性能.最终的试验仿真结果也证明了这一点,因此本文的结果具有重要的实际应用价值.     

Observer Based Projective Synchronization Method for a Class of Chaotic System—Part I: Linear Synchronization Subsystem

In this three-part paper, an observer based projective synchronization method for a class of chaotic system is proposed. At the transmitter, a general observer is used to create the scalar signal for synchronizing. In this part, the structure of the projective synchronization method is presented. And the condition of projection synchronization is theoretically analyzed when the synchronization subsystem is linear.     

基于状态观测器的混沌动态系统跟踪控制

针对一类连续混沌动态系统,提出一种基于状态观测器的跟踪控制方法来进行混沌控制.在引入状态观测器观测混沌动力学系统状态变量的基础上,采用反馈线性化方法将非线性混沌系统转换为线性系统,再针对反馈线性化后的线性系统设计轨迹跟踪控制器,实现被控混沌系统的跟踪控制.仿真结果进一步验证了该方法的有效性.     

Observer Based Projective Synchronization Method for a Class of Chaotic System——Part Ⅰ: Linear Synchronization Subsystem

In this three-part paper, an observer based projective synchronization method for a class of chaotic system is proposed. At the transmitter, a general observer is used to create the scalar signal for synchronizing. In this part, the structure of the projective synchronization method is presented. And the condition of projection synchronization is theoretically analyzed when the synchronization subsystem is linear.     

Observer Based Projective Synchronization Method for a Class of Chaotic System —— Part Ⅰ： Linear Synchronization Subsystem

In this three-part paper, an observer based projective synchronization method for a class of chaotic system is proposed. At the transmitter, a general observer is used to create the scalar signal for synchronizing. In this part, the structure of the projective synchronization method is presented. And the condition of projection synchronization is theoretically analyzed when the synchronization subsystem is linear.     

基于Liu混沌系统同步的图像保密通信研究

分析了Liu混沌系统的特性,讨论了一种观测器同步设计方法.首先对响应系统状态进行重构,然后通过极点配置方法,实现两个混沌系统的状态渐进同步,并通过数值仿真对理论分析加以验证.提出利用Liu混沌系统同步进行图像保密通信的方法,在发送端利用Liu混沌信号掩盖坐标变换后的数字图像信号,在接收端能准确地恢复原始图像信号.仿真结果表明了提出的图像保密通信方法具有很好的保密性.     

基于广义观测器实现混沌系统的同步及信息传输

将保密通信问题看成是信息信号同步问题,从全新的角度提出了一种基于广义观测器的保密通信系统.首先在不改变混沌发送系统的混沌特性的前提下,将信息信号注入到混沌发送系统中,并将其看作系统的状态量;然后在接收端设计广义观测器;最后根据发送端传来的隐藏有信息信号的混沌输出信号同步出混沌系统的状态和信息信号.此方法不需要单独设计加密解密算法,而是将收发端混沌系统的同步与信息传输用同步方法一次实现.对系统的仿真证明了该方法的有效性.     

Feasibility of Analog Realization of a Sliding-Mode Observer: Application to Data Transmission

One of the main contributions of this paper is to highlight the feasibility of analog realization of a chaotic observer-based communication system. The system is composed of a chaotic Colpitts oscillator considered as transmitter and a sliding-mode observer used as receiver. The method used in this realization is based on the synchronization of two chaotic systems (transmitter-receiver). Moreover, another originality of this work is the application of a sliding-mode observer to a Colpitts oscillator, which has a totally different structure with respect to it. Nevertheless, the proposed structure of the observer is designed particularly for this type of oscillator. Only one of the states of the transmitter (chosen according to theoretical criteria) is sent to the receiver which is designed to reconstruct all of the states of the transmitter knowing only the transmitted state. In order to show an application of this work, a message signal is injected into the transmitter using the so-called inclusion method. The message is then recovered by the receiver once all of the transmitter states are reconstructed. Thus, the so-called left inversion problem is resolved experimentally. The whole system (transmitter-observer) is realized using simple and standard analog components, and practical results close to simulations are obtained.     

一类非线性系统的混沌反控制研究

针对一类非线性系统的混沌反控制问题,借用非线性状态观测器概念设计实现混沌反控制的控制器。非混沌系统在控制器的控制下,在与混沌系统的输出实现同步的同时,使非混沌系统处于混沌状态,实现混沌反控制的目标。理论分析及仿真结果都证明该方案的有效性和可行性。     

An Iterative LMI-Based Reduced-Order Observer Design for Fractional-Order Chaos Synchronization

In this paper, attempts are made to design a reduced-order observer for a nonlinear Lipschitz class of fractional-order systems. It is assumed that nonlinear terms not only depend on measurable states but depend on unknown states and inputs as well. The sufficient conditions for stability of the observer based on the Lyapunov technique are derived and converted into linear matrix inequalities (LMIs). To overcome the main drawback of previous research studies which assumed that the sum of terms in infinite series coming from fractional derivative of a Lyapunov function is bounded and its upper bound is predefined, we used an iterative LMI-based algorithm to find out this bound. A four-wing chaotic system is implemented in both PSpice and MATLAB software as a case study. Simulation results are reported to show the effectiveness of the proposed iterative LMI-based reduced-order observer in tracking the unmeasurable state variables of the chaotic fractional system in different initial conditions.     

State-Space Self-Tuning Control for Stochastic Fractional-Order Chaotic Systems

Based on the modified state-space self-tuning control (STC), a novel low-order tuner via the modified observer/Kalman filter identification (OKID) is proposed for stochastic fractional-order chaotic systems. The OKID method is a time-domain technique that identifies a discrete input-output map by using known input-output sampled data in the general coordinate form, through an extension of the eigensystem realization algorithm (ERA). First, the estimated system in the general coordinate based on the conventional OKID method is transformed to the one in an observer form to fit the state-space innovation form for the STC. Then, in stead of the conventional recursive least squares (RLS) identification algorithm used for STC, the Kalman filter as a parameter estimator with the state-space innovation form is presented for effectively estimating the time-varying parameters. Besides, taking the advantage of the digital redesign approach, the derivation of the current-output-based observer is proposed for the modified STC. As a result, the low-order state-space self-tuner with the high-gain controller property is then proposed for stochastic fractional-order chaotic systems, which the fractional operators are well approximated using the standard high integer-order operators. Finally, the fractional-order Chen and Roumlssler systems with stochastic system process and measurement noises are used as illustrative examples to demonstrate the effectiveness of the proposed methodology     

统一混沌系统同步及其保密通信

文中研究了混沌系统的广义同步和基于状态观测器同步。利用这两种同步方法,研究了统一混沌系统同步。研究发现:同步后的响应系统能保持混沌状态。在基于状态观测器同步的基础上,提出了全双工保密混沌通信系统,理论分析和仿真实验证明了该通信方案的可行性。     

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.     

Chen系统和一类统一混沌系统的同步控制

本文利用Lyapunov方法讨论了Chen系统的同步问题以及一类包含Chen系统与Lorenz系统的统一混沌系统的同步问题，所构造的状态反馈同步控制器仅需要一个状态变量，并进行了数值模拟。     

基于重构系统的扩张状态观测器实现混沌系统的同步

利用n阶驱动系统的标量输出信号及其连续的n-1阶导数作为状态变量,得到一个具有Brunowsky规范形式的n阶重构系统.根据扩张观测器的思想,对此重构系统先构造扩张系统,然后设计扩张状态观测器,并将其作为响应系统.通过挖掘可测同步误差中所隐含的信息对扩张系统的各个状态进行估计,从而实现了系统的输出及其导数的同步.当满足一定条件,还可实现所有状态变量的同步.对系统、Duffing系统的仿真证明了该方法的有效性.     

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。     

一个新的三维二次自治混沌系统及其研究

提出了一个新的三维二次自治混沌系统。该系统具有四个参数和两个非线性项,其中的一个参数为分岔参数,二个非线性项分别为乘积项z^2和交叉乘积项xy。随着分岔参数值的改变,系统的振荡机制由周期态演变为混沌态。通过理论分析和计算机模拟以及最大李氏指数和分岔的计算,对系统的基本动力学特性进行了研究。采用模块化设计方法对该系统进行了混沌电路设计与实验,给出了实验结果。电路实验与计算机模拟结果相一致,证实了该系统的混沌特性。     

用细胞神经网络超混沌同步系统实现保密通信

本文提出了一种基于细胞神经网络超混沌同步系统的双通道保密通信系统。用降维观测器思想实现了四阶细胞神经网络超混沌系统的高精度同步，并将其用于双通道混沌保密通信：一个通道传送与信息信号无关的混沌系统的输出信号实现高精度同步，另一个通道传送用混沌信号加密的信息信号。由于同步和加密信号分开传送并且采用了超混沌系统，所设计的保密通信系统具有更高的保密性。