Narrow Results

The problem of the global asymptotic stability for a class of neural networks with time-varying delays is investigated in this paper, where the activation functions are assumed to be neither monotonic, nor differentiable, nor bounded. By constructing suitable Lyapunov functionals and combining with linear matrix inequality (LMI) technique, new global asymptotic stability criteria about different types of time-varying delays are obtained. It is shown that the criteria can provide less conservative result than some existing ones. Numerical examples are given to demonstrate the applicability of the proposed approach.

In this paper a master-slave synchronization scheme is investigated by exploiting a dynamic output feedback control mechanism with time-delay and the influences of time-delay on synchronization are studied. Several new sufficient conditions, which are delay-independent or delay-dependent ones, are presented based on a general class of Lyapunov functions. The obtained results, expressed as matrix inequalities improve and generalize the earlier work in the literature and are readily verified via LMI control toolbox without tuning of parameters and/or matrices. The designs of the controller are implemented by solving a constrained nonlinear optimization problem. Finally, we illustrate our results on Chua's circuits and hyperchaotic attractors.

This study presents an H^∞ controller design for time-delay T-S fuzzy systems based on the fuzzy Lyapunov method, which is defined in terms of fuzzy blending quadratic Lyapunov functions. The delay-dependent robust stability criterion is derived in terms of the fuzzy Lyapunov method to guarantee the stability of time-delay T-S fuzzy systems subjected to disturbances. Based on the delay-dependent condition and parallel distributed compensation (PDC) scheme, the controller design problem is transformed into solving linear matrix inequalities (LMI).

Network-based load frequency control (LFC) requires data transmission from the plant site to the control center and control center to the plant site. Communication delays resulting from an open communication network impart time-varying nature to network delay. This time-varying delay may debase the dynamic performance or instability of the LFC systems. Stability of the LFC system is investigated by Lyapunov–Krasovskii functional (LKF) analysis and linear matrix inequalities (LMIs) techniques. In this paper, a less conservative delay-dependent stability criterion is derived for the time-delay system by proper constructing of LKF and imposing tighter bounding of integral terms on time-derivative of LKF. Delay margin is obtained by solving proposed stability criterion for a time-delay LFC system equipped with a proportional-integral controller. The adequacy of the proposed result is confirmed using simulation studies.