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Xie Y.-H.,Tsinghua University | Xie Y.-H.,Shenyang Artillery Institute | Sun Z.-Q.,Tsinghua University | Sun Z.-Q.,National Laboratory of Space Intelligent Control
Kongzhi Lilun Yu Yingyong/Control Theory and Applications

For a class of delayed Chen chaotic systems with unknown parameters, the scheme of its exponential synchronization is discussed. Based on Lyapunov stability theory, an exponential synchronization controller and adaptive laws of parameters are designed. A sufficient condition of exponential synchronization is then given by using the linear matrix inequality technique. The proposed method is also applied to secure communications. The designed controller is easily implemented in practice. An illustrative example is used to demonstrate the effectiveness of the presented method. Source

Wang X.,Tsinghua University | Guan X.,National Laboratory of Space Intelligent Control | Guan X.,China Academy of Space Technology | Zheng G.,Tsinghua University
Mechanical Systems and Signal Processing

An inverse solution technique with the ability of obtaining complete steady-state primary harmonic responses of local nonlinear structures in the frequency domain is proposed in the present paper. In this method, the nonlinear dynamic equations of motion is first condensed from many to only one algebraic amplitude-frequency equation of relative motion. Then this equation is transformed into a polynomial form, and with its frequency as the unknown variable, the polynomial equation is solved by tracing all the solutions of frequency with the increase of amplitude. With this solution technique, some complicated dynamic behaviors such as sharp tuning, anomalous jumps, breaks in responses and detached resonance curves could be obtained. The proposed method is demonstrated and validated through a finite element beam under force excitations and a lumped parameter model with a local nonlinear element under base excitations. The phenomenon of detached resonance curves in the frequency response and its coupling effects with multiple linear modes in the latter example are observed. © 2015 Elsevier Ltd. Source

Cui J.,Tsinghua University | Guan X.,National Laboratory of Space Intelligent Control | Guan X.,China Academy of Space Technology | Zheng G.,Tsinghua University
International Journal for Numerical Methods in Engineering

A simultaneous iterative procedure for the Kron's component modal synthesis method is developed in this paper for fast calculating the modal parameters of a large-scale and/or complicated structure. To simultaneously improve the precision of all the concerned modal parameters, the modal transformation matrix is chosen as the iterative term. For a faster convergence rate, the reduced system matrices are consistent with the modal transformation matrix. With a mathematically proved consistency and reasonably justified convergence, the proposed method can provide highly accurate results after a few iterations. The implementation details are presented for reference together with some computational considerations. Compared with other methods for obtaining modal parameters, the proposed method has such merits as high computational efficiency and still in a substructuring scheme. Two numerical examples are provided to illustrate and validate the proposed method. © 2016 John Wiley & Sons, Ltd. Source

Yan S.,Intelligent Systems Technology, Inc. | Yan S.,Tsinghua National Laboratory for Information Sciences and Technology | Sun Z.,Intelligent Systems Technology, Inc. | Sun Z.,Tsinghua National Laboratory for Information Sciences and Technology | Sun Z.,National Laboratory of Space Intelligent Control

As the important issue in fuzzy control system, some studies on separation principle for total fuzzy system have been done up to now. However, these existing results are far from enough. In order to supplement such theoretical study, this paper proves that separation principle for T-S fuzzy system with switching fuzzy controller and switching fuzzy observer does hold both in the continuous- and discrete-time case, which can guarantee the stability of total fuzzy system when designing corresponding controller and observer independently. At last, a numerical simulation, some conclusions and discussions about the future work are also presented. © 2010 Elsevier B.V. Source

Luo X.,University of Science and Technology Beijing | Luo X.,National Laboratory of Space Intelligent Control | Li J.,University of Science and Technology Beijing
Science China Information Sciences

The intelligent autonomous control of hypersonic vehicles has aroused great interest from the field of spacecraft. To solve the problem of longitudinal attitude control of hypersonic vehicle in gliding phase, a new intelligent controller is proposed in this paper. This new controller is based on the fuzzy dynamic characteristic modeling method. The fuzzy logic is introduced into the characteristic modeling by dividing the whole restriction range into several subspaces. Simulations show that this modification greatly improves the performance of the original method. With the same whole restriction range the fuzzy dynamic characteristic modeling decreases the time of convergence, and at the same time makes the attitude angle tracing more precise and robust. Since the sub-model is a characteristic model that has stronger adaptiveness than a fixed local model, the number of fuzzy rules is greatly reduced. Our model sharply reduces the complexity in constructing a fuzzy dynamic model. Finally, simulation results are given to show the effectiveness of the proposed approach in dealing with the attitude control problem of hypersonic vehicle in gliding phase. © 2011 Science China Press and Springer-Verlag Berlin Heidelberg. Source

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