一类时滞不确定Lurie系统的鲁棒控制

本文主要讨论了单时滞和多时滞不确定Lurie控制系统的鲁棒绝对稳定性问题，利用Lyapunov方法．结合Razumikhin定理，推导出系统在非结构不确定性下鲁棒绝对稳定的充分条件，并给出相应的算例验证了这个结果。     

基于均匀量化信息通信的有向网络一致性研究

探讨有向非平衡网络多个系统的加权平均一致性问题,研究发现只要固定拓扑有向网络强连通,系统就可以达到一致性。运用广义李雅普诺夫函数对系统进行收敛性分析,并给出仿真图。     

一类多时滞混沌系统的脉冲同步问题的研究

利用Lyapunov稳定性定理和线性矩阵不等式,构造适当的Lyapunov-Krasovskii函数,得到了多时滞混沌系统脉冲同步的充分条件,改进了已有的结果.     

关于一类时滞系统的无条件稳定性

本文对一类单个常时滞系统(1)的无条件稳定性进行了讨论,获得了定理1和定理2。     

一类二阶和三阶时滞微分系统的稳定性

本文证明了自治RFDE系统的Barbashin-Krasovskii定理,对二阶和三阶时滞微分系统进行了研究.     

具有时滞类Lorenz系统的Hopf分岔

本文研究的是关于时滞类Lorenz混沌系统在平衡点的稳定性问题以及产生相应的Hopf分岔的条件。首先对系统引入时滞参量得到平衡点并且判断系统的稳定性,然后通过对系统在平衡点的线性化系统的特征方程根进行分析,得出此系统在平衡点产生Hopf分岔的条件,最后再通过Matlab软件对系统进行数值模拟,所得到的结果与理论分析的结果相同。     

一类不确定离散时滞系统鲁棒镇定的时滞相关研究

本文研究了一类范数有界不确定离散状态时滞系统的鲁棒控制问题.通过采用新的方法,得到了使得系统鲁棒渐近稳定的改进的时滞相关准则,设计了使得系统鲁棒镇定的线性无记忆状态反馈控制器.所得时滞相关准则以严格线性矩阵不等式形式表示,且包含了更少的变量.     

具有时变不确定参数的线性时滞系统的鲁棒镇定

研究了具有时变不确定参数的线性时滞系统的鲁棒镇定问题．提出鲁棒稳定化控制器一种新的设计方法．现有的一些结果可以作为本文的一些特例得到．     

二阶多智能体系统快速一致性分析

提出了二阶多智能体系统快速收敛模型,分析了二阶多智能体系统达到一致性的条件,并对有向网络为动态拓扑结构时多智能体达到一致性的条件给出了理论证明,最后通过仿真对比说明了提出模型的快速性和有效性。     

一类多时滞的向量差分方程的渐近稳定性（英文）

本文讨论了一类具有时滞的差分方程的渐近稳定性。利用矩阵性质和不等式技巧给出了该类方程渐近稳定的充要条件。     

Design of observers for a class of discrete-time uncertain nonlinear systems with time delay

This paper is concerned with the problem of observer design for a class of discrete-time Lipschitz nonlinear state delayed systems with, or without parameter uncertainty. The nonlinearities are assumed to appear in both the state and measured output equations. For both the cases with and without norm-bounded time-varying parameter uncertainties, a design method is proposed, which involves solving a linear matrix inequality (LMI). When a certain LMI is satisfied, the explicit expression of a desired nonlinear observer is also presented. An example is provided to demonstrate the applicability of the proposed approach.     

Consensus of first-order discrete-time multi-agent systems with time delays

This paper mainly considers the consensus for first-order discrete-time multi-agent systems w.r.t. two key parameters, the step size T and the delay τ. First, the consensus is recast into the concurrent stability for a series of trinomials. Then, for each associated trinomial, we derive a necessary and sufficient stability condition, based on proving the two invariance properties for the asymptotic behavior of the critical unitary roots. As a result, the exhaustive consensus region in the $T?\tau$ parameter space (i.e., the parameter set such that the multi-agent system reaches a consensus iff T and τ belong to that set) is determined. Furthermore, we show that the obtained result also applies to systems with diverse input delays, through an extra sufficient consensus condition. Finally, two illustrative examples are presented.     

Consensus stability of a class of second-order multi-agent systems with nonuniform time-delays

This paper is concerned with a consensus problem of a class of second-order multi-agent systems with nonuniform time-delays. A distributed consensus algorithm is adopted to drive all agents to reach consensus and move together with a constant velocity. By a frequency domain approach, an upper bound on the maximum of the time-delays that can be tolerated is given for the consensus of the system.     

Cooperative output regulation problem of multi-agent systems with stochastic packet dropout and time-varying communication delay

In this paper, we deal with the cooperative output regulation problem of linear multi-agent systems on a directed network topology subject to both stochastic packet dropout and time-varying communication delay. On the basis of introducing a queuing mechanism, a distributed state feedback control algorithm is proposed. Then the continuous-time multi-agent systems with piece-wise constant control are converted into discrete-time systems. Under some standard assumptions, the necessary and sufficient conditions under which the tracking errors of followers approach to the origin asymptotically are proposed for different exosystems. Finally, the proposed results are verified via two examples.     

Adaptive observer-based event-triggered finite time formation tracking for multi-agent systems with a non-cooperative leader

The event-triggered time-varying formation tracking for a class of second-order multi-agent systems (MASs) subject to a non-cooperative leader is investigated in this paper. First, in the presence of the unknown input of the leader and external disturbances, a distributed observer with adaptive parameters is put forward for followers to estimate the velocity tracking error. Then, based on the estimated tracking error and an auxiliary variable, a finite time formation controller is further constructed, which is updated depending on a pre-designed event-triggered mechanism. As a result, the desired time-varying formation configuration can be realized in finite time with less communication resource consumption. It’s noted that the constructed formation strategy doesn’t rely on any global information and thus is fully distributed. The stability of the controlled multi-agent system is proved rigorously and it’s verified that event-triggered intervals are with a positive lower bound. At last, simulations are carried out to illustrate the effectiveness of the presented algorithm.     

Robust adaptive sliding mode control for uncertain discrete-time systems with time delay

This paper focuses on robust adaptive sliding mode control for discrete-time state-delay systems with mismatched uncertainties and external disturbances. The uncertainties and disturbances are assumed to be norm-bounded but the bound is not necessarily known. Sufficient conditions for the existence of linear sliding surfaces are derived within the linear matrix inequalities (LMIs) framework by employing the free weighting matrices proposed in He et al. (2008) [3], by which the corresponding adaptive controller is also designed to guarantee the state variables to converge into a residual set of the origin by estimating the unknown upper bound of the uncertainties and disturbances. Also, simulation results are presented to illustrate the effectiveness of the control strategy.     

Observer-based sliding mode control for a class of uncertain nonlinear neutral delay systems

In this paper, the observer-based sliding mode control (SMC) problem is investigated for a class of uncertain nonlinear neutral delay systems. A new robust stability condition is proposed first for the sliding mode dynamics, then a sliding mode observer is designed, based on which an observer-based controller is synthesized by using the SMC theory combined with the reaching law technique. Then, a sufficient condition of the asymptotic stability is proposed in terms of linear matrix inequality (LMI) for the overall closed-loop system composed of the observer dynamics and the state estimation error dynamics. Furthermore, the reachability problem is also discussed. It is shown that the proposed SMC scheme guarantees the reachability of the sliding surfaces defined in both the state estimate space and the state estimation error space, respectively. Finally, a numerical example is given to illustrate the feasibility of the proposed design scheme.     

Output feedback control for stochastic nonlinear time delay systems using dynamic gain technique

This paper investigates the output feedback control for a class of stochastic nonlinear time delay systems based on dynamic gain technique. The nonlinear terms of the stochastic system satisfy linear growth condition on unmeasured state variables with the output dependent incremental rate, which makes the studied time delay stochastic system more general than the exiting results. Firstly, the full order dynamic gain observer is constructed. Then, the linear-like controller is designed without using recursive design method. Next, the stability analysis is given and a useful corollary is obtained. Finally, a simulation is given to illustrate the effectiveness of the proposed method.     

Dynamical behavior in a harvested differential-algebraic prey-predator model with discrete time delay and stage structure

A differential-algebraic model system which considers a prey-predator system with stage structure for prey and harvest effort on predator is proposed. By using the differential-algebraic system theory and bifurcation theory, the dynamic behaviors of the proposed model system with and without discrete time delay are investigated. Local stability analysis of the model system without discrete time delay reveals that there is a phenomenon of singularity induced bifurcation due to variation of the economic interest of harvesting, and a state feedback controller is designed to stabilize the proposed model system at the interior equilibrium; on the other hand, the local stability of the model system with discrete time delay is also studied. The theoretical analysis shows that the discrete time delay has a destabilizing effect in the model of population dynamics, and a phenomenon of Hopf bifurcation occurs as the discrete time delay increases through a certain threshold. Numerical simulations are carried out to show the consistency with theoretical analysis.     

Dual ML-ADHDP method for heterogeneous discrete-time nonlinear multi-agent systems with unknown dynamics and time delay

This paper develops a new dual ML-ADHDP method to solve the optimal consensus problem (OCP) of a class of heterogeneous discrete-time nonlinear multi-agent systems (MASs) with unknown dynamics and time delay. A hierarchical and distributed control strategy is used to transform the original problem into nonlinear model reference adaptive control (MRAC) problems and an OCP of virtual linear MASs. For the nonlinear MRAC problems, a new multi-layer action-dependent heuristic dynamic programming (ML-ADHDP) method is developed to overcome the unknown dynamics and neural network estimation errors, which has higher control accuracy. In order to solve the OCP of virtual linear MASs and improve the convergence speed, a new multi-layer performance index is proposed. Then the ML-ADHDP method is used to solve the coupled Hamiltonian–Jacobi–Bellman equation and obtain the optimal virtual control. Theoretical analysis proves that the original MASs can achieve Nash equilibrium, and simulation results show that the developed dual ML-ADHDP method ensures better convergence speed and higher control accuracy of original MASs.