Meei-Ling Hung

An EP algorithm for stability analysis of interval neutral delay-differential systems

As well-known, evolutionary programming (EP) algorithms have been considered as promising techniques for global optimal search. The main objective of this paper is to develop a novel EP algorithm for the robust stability analysis of interval neutral delay-differential systems. Two main results are obtained in this paper. First a delay-dependent criterion is derived for ensuring the stability of degenerate neutral time-delay systems, and then by solving some optimization problems, which will be defined later, the robust stability of interval neutral delay-differential systems can be guaranteed. Two numerical examples are given to illustrate the results.

Design of active queue management algorithms for TCP networks: Nonlinear output feedback approach

This paper is concerned with the design of robust active queue management (AQM) controllers for a class of TCP networks. In TCP/IP networks, the packet-dropping probability function is limited between 0 and 1. Therefore, a TCP network with AQM controller was modeled as a rate-based non-linear system with a saturated input. The nonlinear output feedback AQM controller is proposed for achieving the desired queue size and guaranteeing asymptotic stability of the operating point. The performance and effectiveness of the proposed control laws are validated for serial network scenarios through numerical simulations by Network Simulator-2 (NS-2). Simulation results confirm that the proposed scheme outperforms other AQM schemes.

Intelligent control design and implementation of DC servo motor

This study focuses on the position feedback control problem of DC servo motors. A suitable IAE fitness function is selected, and then the methods of GA and EP are used to find the optimal PID control gain constants. Basing on these optimal PID control gain constants, we add an FLC to the constants to make them the fine tuning gain constants. The result shows that a better control response can be obtained by combining the FLC with optimal PID control. Finally, a DC servo motor produced by Quanser Inc. is used to verify its effectiveness.

Chaos suppression of generalized Lorenz system: Adaptive fuzzy sliding mode control approach

This study presents the chaos suppression for generalized Lorenz system via an adaptive fuzzy sliding mode controller (AFSMC). The proposed scheme can asymptotically drive the state trajectory of the generalized Lorenz system with unknown parameter to a desired switching surface and ensure the stability of the closed-loop system. In addition, the control signal is chattering free by the AFSMC reaching law that is inferred a set of fuzzy logic rules with output of sliding mode controller (SMC). A numerical simulation is included to illustrate the feasibility and effectiveness of the proposed scheme.

Robust Controlling Chaos for Unified Chaotic Systems via Sliding Mode Control

This study investigates the stabilization problem for uncertain unified chaotic systems with input nonlinearity. A sliding mode control technique is adopted to facilitate the robustness of controlled systems and an adaptive switching surface is newly proposed to simplify the task of assigning the stability of the closed-loop system in sliding motion. This controller is robust to the nonlinear input and guarantees the occurrence of sliding motion of the controlled unified chaotic systems with uncertainties. Incidentally, in the sliding mode, the investigated uncertain chaotic system with input nonlinearity still possesses advantages of fast response, good transient performance and insensitive to the uncertainties as the systems with linear input.

Robust Synchronization of Fractional Lorenz Systems Containing Nonlinear Inputs

The problem of synchronization for fractional master-slave Lorenz chaotic systems coupled with sector nonlinear control input is investigated. Using the sliding mode control technique, a control scheme containing a new fraction-integer integral (FII) switching surface is developed to guarantee the synchronization of fractional Lorenz chaotic systems even when the sector nonlinearity is present. Numerical simulations are included to demonstrate the effectiveness of the proposed synchronization scheme.

Impulsive synchronization of chaotic systems via linear matrix inequality approach

The aim of this paper is to propose an impulsive controller which is to guarantee the asymptotic synchronization of the master and slave chaotic systems. The impulsive controller is derived on the basis of the Lyapunov theory and the linear matrix inequlity (LMI) technique. A numerical example is given to demonstrate the effectiveness of the main results.