A robust adaptive fuzzy control scheme is presented for a class of strict-feedback nonaffine nonlinear systems with modeling uncertainties and external disturbances by using a backstepping approach.Fuzzy logic systems...A robust adaptive fuzzy control scheme is presented for a class of strict-feedback nonaffine nonlinear systems with modeling uncertainties and external disturbances by using a backstepping approach.Fuzzy logic systems are employed to approximate the unknown parts of the desired virtual controls,and the approximation errors of fuzzy systems are only required to be norm-bounded.The function tanh（·） is introduced to avoid problems associated with sgn（·）.The tracking error is guaranteed to be uniformly ultimately bounded with the aid of an additional adaptive compensation term.Chua＇s circuit system and R o¨ssler system are presented to illustrate the feasibility and effectiveness of the proposed control technique.展开更多
Some new criteria for the chaotic lag synchronization are proposed. At first,lag synchronization scheme for identical master-slave Lur‘ e systems by replacing variables control and the relevant error system are given...Some new criteria for the chaotic lag synchronization are proposed. At first,lag synchronization scheme for identical master-slave Lur‘ e systems by replacing variables control and the relevant error system are given, and the relations between absolute stability of the error system and the chaotic lag synchronization are described. Then, based on a quadratic Lyapunov function, two new Lur‘ e criteria for the above chaotic lag synchronization are proved. Four corresponding frequency domain criteria are further derived by means of Meyer-Kalman-Yacubovia Lemma. These frequency domain criteria are applied to analyze the lag synchronization of general master-slave Chua's circuits so that some ranges of the parameters in which the master-slave Chua's circuits achieve chaotic lag synchronization by replacing single-variable control are attained. Finally, some examples are given to verify the theoretical results.展开更多
Chaos synchronization has been applied in secure communication, chemicalreaction, biological systems, and information processing. A new theorem to synchronization ofunified chaotic systems via adaptive control is prop...Chaos synchronization has been applied in secure communication, chemicalreaction, biological systems, and information processing. A new theorem to synchronization ofunified chaotic systems via adaptive control is proposed. The constructive theorem provides thedesign scheme for adaptive controller such that a respond system can synchronize with respect to anuncertain drive system. One example for discontinuous chaotic system is proposed to illustrate theeffectiveness and feasibility.展开更多
通信安全是混沌理论最有前景的重要应用之一。为提高系统的安全性能,本文利用多组耦合蔡氏电路设计了一套通信安全系统。首先,基于经典蔡氏电路及其常规改进方法提出了一种新的改进方法,该方法将原电路中电容电压信号作乘法运算后,与原...通信安全是混沌理论最有前景的重要应用之一。为提高系统的安全性能,本文利用多组耦合蔡氏电路设计了一套通信安全系统。首先,基于经典蔡氏电路及其常规改进方法提出了一种新的改进方法,该方法将原电路中电容电压信号作乘法运算后,与原信号一同构成扩展信号,实现经典蔡氏电路的维数扩展。对所提改进电路的理论分析和基于Matlab/Simulink及Multisim的仿真研究表明:该改进蔡氏电路完整保留了蔡氏电路的特性,扩展信号具有更加丰富的混沌现象,可以观测到一个新的四翅蝴蝶吸引子;部分变量桥式耦合技术可以实现对改进电路的良好控制;其次,利用改进电路构成的多组耦合电路合成通信安全系统加密及解密信号,以此掩盖信息实现信息的安全传输,其中加密信号的运算方式相当于系统的二次加密,提高了系统的保密性能;利用一个15 m V的锯齿信号对本文所设计的系统进行测试,结果表明:所设计的系统的传输误差仅为0.5%,本系统具有良好的系统安全性能、灵活性及可扩展性。该改进蔡氏电路通信安全系统的设计原理可以作为利用DSP、集成电路等实现类似通信安全系统的基础,具有极大的深入研究价值。展开更多
基金supported by the National Natural Science Foundation of China (9071602811001128)
文摘A robust adaptive fuzzy control scheme is presented for a class of strict-feedback nonaffine nonlinear systems with modeling uncertainties and external disturbances by using a backstepping approach.Fuzzy logic systems are employed to approximate the unknown parts of the desired virtual controls,and the approximation errors of fuzzy systems are only required to be norm-bounded.The function tanh（·） is introduced to avoid problems associated with sgn（·）.The tracking error is guaranteed to be uniformly ultimately bounded with the aid of an additional adaptive compensation term.Chua＇s circuit system and R o¨ssler system are presented to illustrate the feasibility and effectiveness of the proposed control technique.
基金This work was supported by the National Natural Science Foundation of China (No. 10371136)the Natural Science Foundation of Guangdong Province of China (No.021765).
文摘Some new criteria for the chaotic lag synchronization are proposed. At first,lag synchronization scheme for identical master-slave Lur‘ e systems by replacing variables control and the relevant error system are given, and the relations between absolute stability of the error system and the chaotic lag synchronization are described. Then, based on a quadratic Lyapunov function, two new Lur‘ e criteria for the above chaotic lag synchronization are proved. Four corresponding frequency domain criteria are further derived by means of Meyer-Kalman-Yacubovia Lemma. These frequency domain criteria are applied to analyze the lag synchronization of general master-slave Chua's circuits so that some ranges of the parameters in which the master-slave Chua's circuits achieve chaotic lag synchronization by replacing single-variable control are attained. Finally, some examples are given to verify the theoretical results.
基金This project is jointly supported by the National Natural Science Foundation of China(No.60074034,No.70271068),the Research Fund for the Doctoral Program of Higher Education(No.200020008004)and the Foundation for University Key Teacher by the Ministry of
文摘Chaos synchronization has been applied in secure communication, chemicalreaction, biological systems, and information processing. A new theorem to synchronization ofunified chaotic systems via adaptive control is proposed. The constructive theorem provides thedesign scheme for adaptive controller such that a respond system can synchronize with respect to anuncertain drive system. One example for discontinuous chaotic system is proposed to illustrate theeffectiveness and feasibility.
文摘通信安全是混沌理论最有前景的重要应用之一。为提高系统的安全性能,本文利用多组耦合蔡氏电路设计了一套通信安全系统。首先,基于经典蔡氏电路及其常规改进方法提出了一种新的改进方法,该方法将原电路中电容电压信号作乘法运算后,与原信号一同构成扩展信号,实现经典蔡氏电路的维数扩展。对所提改进电路的理论分析和基于Matlab/Simulink及Multisim的仿真研究表明:该改进蔡氏电路完整保留了蔡氏电路的特性,扩展信号具有更加丰富的混沌现象,可以观测到一个新的四翅蝴蝶吸引子;部分变量桥式耦合技术可以实现对改进电路的良好控制;其次,利用改进电路构成的多组耦合电路合成通信安全系统加密及解密信号,以此掩盖信息实现信息的安全传输,其中加密信号的运算方式相当于系统的二次加密,提高了系统的保密性能;利用一个15 m V的锯齿信号对本文所设计的系统进行测试,结果表明:所设计的系统的传输误差仅为0.5%,本系统具有良好的系统安全性能、灵活性及可扩展性。该改进蔡氏电路通信安全系统的设计原理可以作为利用DSP、集成电路等实现类似通信安全系统的基础,具有极大的深入研究价值。
