Hexin Zhang

Delay-partitioning approach for systems with interval time-varying delay and nonlinear perturbations

This paper considers the problem of robust stability for a class of linear systems with interval time-varying delay and nonlinear perturbations. Less conservative stability criteria was put forward by using delay-partitioning approach. By decomposing the delay interval into multiple equidistant subintervals, new Lyapunov-Krasovskii (L-K) functional contains some triple-integral terms and augment terms which are introduced on these intervals, thus resulting in being much less conservative than most existing results in the literature. In addition, in deriving the stability conditions in linear matrix inequality (LMI) framework, neither model transformations nor superfluous free-weighting matrix are employed for dealing the cross-terms that emerge from the time derivative of the L-K functional; instead, they are dealt using tighter integral inequalities which only contain a minimal number of slack matrix variables. Numerical examples are given to demonstrate the effectiveness of the proposed approach.

Improved Results on Robust Stability for Systems with Interval Time-Varying Delays and Nonlinear Perturbations

This paper investigated delay-dependent robust stability criteria for systems with interval time-varying delays and nonlinear perturbations. A delay-partitioning approach is used in this paper, the delay-interval is partitioned into multiple equidistant subintervals, a new Lyapunov-Krasovskii (L-K) functional contains some triple-integral terms, and augment terms are introduced on these intervals. Then, by using integral inequalities method together with free-weighting matrix approach, a new less conservative delay-dependent stability criterion is formulated in terms of linear matrix inequalities (LMIs), which can be easily solved by optimization algorithms. Numerical examples are given to show the effectiveness and the benefits of the proposed method.

Novel robust stability condition for uncertain neutral systems with mixed time-varying delays

In this article, the issue of robust stability analysis for a sort of uncertain neutral system with mixed time-varying delays is studied. A new Lyapunov–Krasovskii functional comprising quadruple-integral term is introduced so as to develop a less conservative stability condition. A novel discrete and neutral delay-dependent stability criterion based on linear matrix inequalities is given using delay-central point method as well as reciprocally convex combination approach, which is derived by integral inequality approach. Compared with the existing literature, this criterion can greatly reduce the complexity of theoretical derivation and computation. Finally, three numerical comparative examples are designated to verify the superiority of the proposed approach in reducing the conservation of conclusion.

Some new results on model-based event-triggered state feedback control

Model-based event-triggered state feedback control method can significantly reduce communication in networked control systems. Based on the exactly investigates the disturbance impact on event triggering, we found that the event triggering in model-based event-triggered state feedback control is sensitive to the varying degree of disturbances but not the magnitude of disturbances. In this paper, some new results are given about model-based event-triggered control, these results also verified by simulation.

Improve results on delay-dependent robust H∞ control for uncertain systems with interval time-varying delay

This paper considers the delay-dependent robust H∞ control problem for a class of linear systems with interval time-varying delay and norm-bounded uncertainties. An improved delay-dependent bounded real lemma (BRL) for the systems is established based on a new candidate Lyapunov-Krasovskii (L-K) functional and linear matrix inequality (LMI). Then by applying the BRL, a memoryless state feedback H∞ controller such that the resulting closed-loop system is asymptotically stable and satisfied a prescribed H∞ performance level for all admissible uncertainties is deduced. Finally, numerical examples are provided to demonstrate the effectiveness and benefits of the proposed method.