Passivity analysis for uncertain stochastic neural networks with discrete interval and distributed time-varying delays

The problem of passivity analysis is investigated for uncertain stochastic neural networks with discrete interval and distributed time-varying delays. The parameter uncertainties are assumed to be norm bounded and the delay is assumed to be time-varying and belongs to a given interval, which means that the lower and upper bounds of interval time-varying delays are available. By constructing proper Lyapunov-Krasovskii functional and employing a combination of the free-weighting matrix method and stochastic analysis technique, new delay dependent passivity conditions are derived in terms of linear matrix inequalities (LMIs). Finally, numerical examples are given to show the less conservatism of the proposed conditions.     

基于LMIs方法-不确定性随机分布型时滞Markov跳变系统的鲁棒镇定

研究了一类具有不确定性Markov跳变参数的线性分布型时滞系统.考虑了具不确定性、Markov跳变参数、及分布型时滞系统的鲁棒均方稳定性问题.设计了系统的鲁棒状态反馈镇定控制器.采用了Grownwall Bellman不等式,基于线性矩阵不等式(LMIs)方法,给出了鲁棒稳定性的LMI时滞依赖的代数判据,从而降低了判据的保守性.同时得到了相应的离散时滞情形下的结果.     

Robust H∞ control for neutral stochastic uncertain systems with time-varying delay

The problem of robust H∞ control for uncertain neutral stochastic systems with time-varying delay is discussed.The parameter uncertaintie is assumed to be time varying norm-bounded.First,the stochastic robust stabilization of the stochastic system without disturbance input is investigated by nonlinear matrix inequality method.Then,a full-order stochastic dynamic output feedback controller is designed by solving a bilinear matrix inequality(BMI),which ensures a prescribed stochastic robust H∞ performance level for the resulting closed-loop system with nonzero disturbance input and for all admissible uncertainties.An illustrative example is provided to show the feasibility of the controller and the potential of the proposed technique.     

一类具输入时滞的分布参数系统移动控制

基于移动传感器/执行器网络,研究了一类具有输入时滞的分布参数系统稳定性控制问题。利用抽象发展方程理论、算子半群理论和Lyapunov稳定性定理,设计系统的反馈控制器;再结合移动传感器/执行器的动力学行为,设计其控制力。证明了在反馈控制器和控制力的作用下,分布参数系统在具输入时滞情况下是渐近稳定的。通过数值仿真实验表明,不同的输入时滞,对系统的稳定效果有一定的影响,但在控制力的作用下,系统都能趋于稳态,说明本文中对于具有输入时滞的分布参数系统的控制策略是有效的。     

一类具输入时滞的分布参数系统移动控制

基于移动传感器/执行器网络,研究了一类具有输入时滞的分布参数系统稳定性控制问题。利用抽象发展方程理论、算子半群理论和Lyapunov稳定性定理,设计系统的反馈控制器;再结合移动传感器/执行器的动力学行为,设计其控制力。证明了在反馈控制器和控制力的作用下,分布参数系统在具输入时滞情况下是渐近稳定的。通过数值仿真实验表明,不同的输入时滞,对系统的稳定效果有一定的影响,但在控制力的作用下,系统都能趋于稳态,说明本文中对于具有输入时滞的分布参数系统的控制策略是有效的。     

Robust H∞ control for neutral stochastic uncertain systems with time-varying delay

The problem of robust H∞ control for uncertain neutral stochastic systems with time-varying delay is discussed. The parameter uncertaintie is assumed to be time varying norm-bounded. First, the stochastic robust stabilization of the stochastic system without disturbance input is investigated by nonlinear matrix inequality method. Then, a full-order stochastic dynamic output feedback controller is designed by solving a bilinear matrix inequality (BMI), which ensures a prescribed stochastic robust H∞ performance level for the resulting closed loop system with nonzero disturbance input and for all admissible uncertainties. An illustrative example is provided to show the feasibility of the controller and the potential of the proposed technique.     

Stability of stochastic switched epidemic systems with discrete or distributed time delay

Stochastic switched epidemic systems with a discrete or distributed time delay are constructed and investigated. By the Lyapunov method and lto＇s differential rule, the existence and uniqueness of global positive solution of each system is proved. And stability conditions of the disease-free equilibrium of the systems are obtained. Numerical simulations are presented to illustrate the results.     

H_∞-based fault detection for nonlinear networked systems with random packet dropout and probabilistic interval delay

The fault detection problem for the nonlinear networked control system(NCS) with packet dropout and delay is investigated.A nonlinear stochastic system model is proposed to account for the NCS with random packet dropout and networkinduced non-uniformly distributed time-varying delay in both from sensor to controller(S/C) and from controller to actuator(C/A).Based on the obtained NCS model,employing an observer-based fault detection filter as the residual generator,the addressed fault detection problem is converted into an auxiliary nonlinear H∞ control problem.Then,with the help of Lyapunov functional approach,a sufficient condition for the desired fault detection filter is constructed in terms of certain linear matrix inequalities,which depend on not only the delay interval but also the delay interval occurrence rate and successful packet communication rate.Especially,a trade-off phenomenon between the maximum allowable delay bound and successful data packet transmission rate is found,which is typically resulted from the limited bandwidth of communication networks.The effectiveness of the proposed method is demonstrated by a simulation example.     

欠阻尼对象的最优PID控制器参数整定方法

研究了带有纯延迟的欠阻尼对象最优PID控制器的参数整定及性能鲁棒性评价问题。首先依据频域判据，确定保证闭环系统稳定的PID控制器参数域，然后采用全局寻优的遗传算法，获得ITAE指标最优的PID控制器参数。采用蒙特卡罗随机实验方法，对模型参数在有界范围内摄动时的性能鲁棒性进行了定量的比较和评价。仿真结果表明，本文方法具有良好的动态性能，在对象参数摄动时与极点配置方法和幅值相位裕量方法相比具有较好的性能鲁棒性。     

Maximum principle for partially-observed optimal control problems of stochastic delay systems

This paper is concerned with partially-observed optimal control problems for stochastic delay systems. Combining Girsanov’s theorem with a standard variational technique, the authors obtain a maximum principle on the assumption that the system equation contains time delay and the control domain is convex. The related adjoint processes are characterized as solutions to anticipated backward stochastic differential equations in finite-dimensional spaces. Then, the proposed theoretical result is applied to study partially-observed linear-quadratic optimal control problem for stochastic delay system and an explicit observable control variable is given.     

Delay-dependent exponential stability of impulsive stochastic systems with time-varying delay

The problem of delay-dependent exponential stability is investigated for impulsive stochastic systems with time-varying delay.Although the exponential stability of impulsive stochastic delay systems has been discussed by several authors,few works have been done on delay-dependent exponential stability of impulsive stochastic delay systems.Firstly,the Lyapunov-Krasovskii functional method combing the free-weighting matrix approach is applied to investigate this problem.Some delay-dependent mean square exponential stability criteria are derived in terms of linear matrix inequalities.In particular,the estimate of the exponential convergence rate is also provided,which depends on system parameters and impulsive effects.The obtained results show that the system will stable if the impulses’ frequency and amplitude are suitably related to the increase or decrease of the continuous flows,and impulses may be used as controllers to stabilize the underlying stochastic system.Numerical examples are given to show the effectiveness of the results.     

Robust reliable guaranteed cost control for nonlinear singular stochastic systems with time delay

To study the design problem of robust reliable guaranteed cost controller for nonlinear singular stochastic systems,the Takagi-Sugeno(T-S)fuzzy model is used to represent a nonlinear singular stochastic system with norm-bounded parameter uncertainties and time delay.Based on the linear matrix inequality(LMI)techniques and stability theory of stochastic differential equations,a stochastic Lyapunov function method is adopted to design a state feedback fuzzy controller.The resulting closed-loop fuzzy system is robustly reliable stochastically stable,and the corresponding quadratic cost function is guarauteed to be no more than a certain upper bound for all admissible uncertainties,as well as different actuator fault cases.A sufficient condition of existence and design method of robust reliable guaranteed cost controller is presented.Finally,a numerical simulation is given to illustrate the effectiveness of the proposed method.     

参数效应的仿真与反馈环及延迟三组合分析法——以场供给侧改革为例

规划落实、政策执行、措施实施皆是通过参数调控系统相关发展速度实现,为此进行参数调控流率效应方法研究.调控流率效应研究必须建立参数调控的可靠性高的模型,必须进行仿真、反馈环、延迟3组合分析,才可能具体清楚回答运行中的问题,实际应用需要,查文献还未见此种三组合分析法,为此,进行"参数调控流率入树建模和仿真、反馈环、延迟三组合分析法"研究.顶天立地,通过南昌大学系统工程科研教学基地明鑫农场供给侧改革,生产雷竹笋、有机鱼、有机生猪特色农产品系统实例,阐述此"三组合分析法".首先基于逐树设撤关联数结构行为检验法,建立场的8参数调控的8棵流率基本入树可靠性高的模型.接着,依据实际分析与场规划,分别确定8参数的调控区间,设参数的调控区间最小值组合为最不满意方案,区间最大值组合为最满意方案,对两方案进行参数调控效应仿真分析.随后,建立8阶参数枝向量行列式计算反馈环,获12条参数调控反馈环.接着,分别围绕雷竹笋产业、有机鱼产业和开发青饲料发展有机猪促进圈养猪转型3个子系统的6条反馈环分别进行反馈环结构图、反馈环正负极性、延迟阶数确定研究后,进行仿真、反馈环、延迟3结合具体分析结果,然后,依据3结合的具体分析和反馈环、延迟原理,提出了供给侧改革的操作性强的管理思路与技术.通过研究,建立了实际背景强的"参数调控入树流率建模和仿真、反馈环、延迟三组合分析"新方法.     

Robust reliable guaranteed cost control for nonlinear singular stochastic systems with time delay

To study the design problem of robust reliable guaranteed cost controller for nonlinear singular stochastic systems, the Takagi-Sugeno （T-S） fuzzy model is used to represent a nonlinear singular stochastic system with norm-bounded parameter uncertainties and time delay. Based on the linear matrix inequality （LMI） techniques and stability theory of stochastic differential equations, a stochastic Lyapunov function method is adopted to design a state feedback fuzzy controller. The resulting closed-loop fuzzy system is robustly reliable stochastically stable, and the corresponding quadratic cost function is guaranteed to be no more than a certain upper bound for all admissible uncertainties, as well as different actuator fault cases. A sufficient condition of existence and design method of robust reliable guaranteed cost controller is presented. Finally, a numerical simulation is given to illustrate the effectiveness of the proposed method.     

基于比较利益下农业生产模式的模型研究

在连续时间的假设下,研究了农业产出量服从几何布朗运动的最优控制问题。首先借助于马尔可夫过程理论确定出转移概率密度,再利用分布参数系统模型来描述某个地域的粮食和经济作物的产出量在随机变化的情况下,农业生产的分布模型。最后探讨了在均衡条件下农业生产者以寻求利益最大化为目的的最优控制方程。同时给出了某地域粮食及经济作物的产量预测分析模型。参9。     

Distributed quantized consensus for agents on directed networks

Communication bandwidth and network topology are two important factors that affect performance of distributed consensus in multi-agent systems. The available works about quantized average consensus assume that the adjacency matrices associated with the digraphs are doubly stochastic, which amounts to that the digital networks are balanced. However, this assumption may be unrealistic in practice. In this paper, without assuming double stochasticity, the authors revisit an existing quantized average consensus protocol with the logarithmic quantization scheme, and investigate the quantized consensus problem in general directed digital networks that are strongly connected but not necessarily balanced. The authors first derive an achievable upper bound of the quantization precision parameter to design suitable logarithmic quantizer, and this bound explicitly depends on network topology. Subsequently, by means of the matrix transformation and the Lyapunov techniques, the authors provide a testable condition under which the weighted average consensus can be achieved with the proposed quantized protocol.     

Ho∞-based fault detection for nonlinear networked systems with random packet dropout and probabilistic interval delay

The fault detection problem for the nonlinear networked control system (NCS) with packet dropout and delay is investigated.A nonlinear stochastic system model is proposed to account for the NCS with random packet dropout and networkinduced non-uniformly distributed time-varying delay in both from sensor to controller (S/C) and from controller to actuator (C/A).Based on the obtained NCS model,employing an observer-based fault detection filter as the residual generator,the addressed fault detection problem is converted into an auxiliary nonlinear H∞ control problem.Then,with the help of Lyapunov functional approach,a sufficient condition for the desired fault detection filter is constructed in terms of certain linear matrix inequalities,which depend on not only the delay interval but also the delay interval occurrence rate and successful packet communication rate.Especially,a trade-off phenomenon between the maximum allowable delay bound and successful data packet transmission rate is found,which is typically resulted from the limited bandwidth of communication networks.The effectiveness of the proposed method is demonstrated by a simulation example.     

基于分布参数系统的耕地可持续发展问题的建模与优化

在连续时间模型的假设条件下,充分研究了农业耕地中有机物含量及微量元素含量的随机变化过程,首先借助于马尔可夫过程理论确定出转移概率密度函数,然后利用扩散随机过程理论及分布参数系统建立模型描述耕地肥力的状况,探讨了在保证耕地质量的前提下以农业生产者投资收益最大化作为目标值的最优控制问题。最后,给出了某时刻农用耕地肥力水平的预测方程。为充分发挥土地的使用价值及农业的可持续发展提供科学的依据。     

Stochastic stabilization analysis of networked control systems

Considering the stochastic delay problems existing in networked control systems, a new control mode is proposed for networked control systems whose delay is longer than a sampling period. Under the control mode, the mathematical model of such a system is established. A stochastic stabilization condition for the system is given. The maximum delay can be derived from the stabilization condition.     

单重延误休假的$M^x$/G(M/G)/1可修排队系统分析(Ⅰ)—— 一些排队指标

考虑具有单重延误休假的$M^x$/G(M/G)/1可修排队系统,其中休假时间、服务时间、修理时间和延误休假时间都为任意分布(不一定是连续型),采用一种较简洁的方法,我们获得队长的瞬态解、平稳解和队长的随机分解表达式,同时给出了一些特殊情形下队长的随机分解结果.