Zhang Qing-ling

New approaches to H∞ controller designs based on fuzzy observers for T-S fuzzy systems via LMI

The problems of relaxed quadratic stability conditions, fuzzy observer designs and H∞ controller designs for T-S fuzzy systems have been studied. First new stability conditions are obtained by relaxing the stability conditions derived in previous papers. Secondly, new fuzzy observers based on the relaxed stability conditions for the T-S fuzzy systems have been proposed. Thirdly two su8cient LMI conditions, which guarantee the existence of the H∞ controllers based on fuzzy observers for the T-S fuzzy systems have been proposed. The conditions are not only simple, but also consider the interactions among the fuzzy subsystems. Finally by some examples, using the LMI technique, we show that the regulators, the fuzzy observers and the H∞ controller designs based on new observers for the T-S fuzzy systems are very practical and e8cient. ? 2003 Elsevier Ltd. All rights reserved.

Stabilization of networked control systems via periodically time-varying local controller

This paper is concerned with the design problem of the periodically time-varying local controller for networked control systems. In terms of the feasible solutions to linear matrix inequalities (LMIs), a necessary and sufficient condition is derived via the usage of networks in the context of decentralized control, and the set of periodically time-varying (PTV) local controller can be derived. Furthermore, an example is given to illustrate the effectiveness of the conclusion.

H/sub /spl infin// controller designs based on fuzzy observers for T-S fuzzy systems via LMI

In this paper, first new sufficient conditions in the terms of LMIs, which guarantee the existence of the fuzzy observers for the T-S fuzzy systems, has been proposed. Secondly two sufficient conditions in the terms of LMIs, which guarantee the existence of the H/sub /spl infin// control based on fuzzy observers for the T-S fuzzy systems have been proposed. The fuzzy observers and the H/sub /spl infin// controller designs based on observers for the T-S fuzzy systems are very practical and efficient.

State feedback stabilization for switched singular networked control systems with time-delay

In this paper, the problem of state feedback stabilization for switched singular networked control systems with time-delay is considered. Firstly, the modeling problem is discussed. Suppose the sensor node is time-driven, the controller and executor are event-driven, assuming the sensor data are transmitted with single data packed and the transfer delay is less than one sampled period, the system can be modeled as an linear discrete switched system with delay. By Lyapunov function, we can easily determine the stability of the systems. Using Matlab LMI toolbox, we can obtain the state feedback control law at the same time. Finally, an example is presented to illustrate that the proposed method is efficient.

Adaptive control of bifurcation and chaos in a time-delayed system

In this paper, the stabilization of a continuous time-delayed system is considered. To control the bifurcation and chaos in a time-delayed system, a parameter perturbation control and a hybrid control are proposed. Then, to ensure the asymptotic stability of the system in the presence of unexpected system parameter changes, the adaptive control idea is introduced, i.e., the perturbation control parameter and the hybrid control parameter are automatically tuned according to the adaptation laws, respectively. The adaptation algorithms are constructed based on the Lyapunov-Krasovskii stability theorem. The adaptive parameter perturbation control and the adaptive hybrid control methods improve the corresponding constant control methods. They have the advantages of increased stability, adaptability to the changes of the system parameters, control cost saving, and simplicity. Numerical simulations for a well-known chaotic time-delayed system are performed to demonstrate the feasibility and superiority of the proposed control methods. A comparison of the two adaptive control methods is also made in an experimental study.

Elimination of spiral waves and spatiotemporal chaos by the synchronization transmission technology of network signals

A method to eliminate spiral waves and spatiotemporal chaos by using the synchronization transmission technology of network signals is proposed in this paper. The character of the spiral waves and the spatiotemporal chaos in the Fitzhugh—Nagumo model is presented. The network error evolution equation with spatiotemporal variables and the corresponding eigenvalue equation are determined based on the stability theory, and the global synchronization condition is obtained. Simulations are made in a complex network with Fitzhugh—Nagumo models as the nodes to verify the effectiveness of the synchronization transmission principle of the network signal.

Graphic theory on interval stability of networked control systems

Abstract A new method on the interval stability of networked control systems (NCSs) with random delay and data packet dropout is studied. Combining interval systems and NCSs, a graphic condition on judging interval stability is presented in terms of the weighted diagraph theory in graph theory. Furthermore, utilizing the graph-theoretic algorithm, the delay-depended controller gains are obtained. Aiming at the same delay and data packed dropout, several controller gains are obtained, simultaneously. The example and simulation illustrate the effectiveness of the proposed method.

Backstepping synchronization of uncertain chaotic systems by a single driving variable

In this paper a parameter observer and a synchronization controller are designed to synchronize unknown chaotic systems with diverse structures. Based on stability theory the structures of the observer and the controller are presented. The unknown Coullet system and Rossler system are taken for examples to demonstrate that the method is effective and feasible. The artificial simulation results show that global synchronization between the unknown Coullet system and the Rossler system can be achieved by a single driving variable with co-operation of the observer and the controller, and all parameters of the Coullet system can be identified at the same time.

Derivative Feedback Control for Singular Systems

A survey of derivative feedback control for singular systems is presented. Emphasis is put on the regularization of singular systems as well as eigenstructure assignment developed in recent years. Finally, some prospective topics are outlined.

Adaptive synchronization of uncertain chaotic systems via switching mechanism

This paper deals with the problem of synchronization for a class of uncertain chaotic systems. The uncertainties under consideration are assumed to be Lipschitz-like nonlinearity in tracking error, with unknown growth rate. A logic-based switching mechanism is presented for tracking a smooth orbit that can be a limit cycle or a chaotic orbit of another system. Based on the Lyapunov approach, the adaptation law is determined to tune the controller gain vector online according to the possible nonlinearities. To demonstrate the efficiency of the proposed scheme, the well-known chaotic system namely Chuas circuit is considered as an illustrative example.