不确定时滞系统的鲁棒绝对稳定性研究

基于Lyapunov稳定性理论，采用线性矩阵不等式处理方法，研究具有参数不确定性的时滞系统鲁棒绝对稳定性问题．导出了用线性矩阵不等式系统可行性描述的系统鲁棒绝对稳定的滞后依赖型条件，据此可计算出最大的允许时滞界．通过求解一组线性矩阵不等式，给出使得闭环系统鲁棒绝对稳定的无记忆状态反馈控制律设计方法。     

具有多状态和控制时滞的控制系统的绝对稳定性分析

基于线性矩阵不等式方法, 对具有多个状态和控制的时变时滞的Lurie型控制系统的稳定性进行分析, 得到了系统绝对稳定的几个充分条件, 这些条件用线性矩阵不等式表示, 具有较低的保守性. 最后通过一个实例验证了所得条件的保守性较以往结果的保守性小.     

基于增广Lyapunov泛函的Lurie时滞系统的绝对稳定性

对Lurie时滞系统的绝对稳定性问题进行了研究. 利用增广的Lyapunov泛函结合自由权矩阵方法, 得到了系统基于线性矩阵不等式(LMI)的时滞相关绝对稳定条件. 数值实例表明本文方法所得结果要优于现有文献中的结果.     

一类含未建模动态的奇异时滞系统的鲁棒镇定问题

利用线性矩阵不等式的方法,研究了一类同时含有参数摄动和未建模动态的线性奇异时滞系统的鲁棒镇定问题.得到了系统可鲁棒镇定的一个充分条件,用线性矩阵不等式的方法,将控制器的求解问题转化为受限线性矩阵不等式的求解问题,并给出了受限线性矩阵不等式的具体解法．最后举例说明了所提出方法的正确性．     

含状态时滞及执行器饱和不确定系统反馈镇定及L2增益分析

研究了具有控制饱和状态时滞不确定系统的L2控制问题,提出了状态反馈方法,利用Lyapunov函数可获得时滞相关的线性矩阵不等式.线性矩阵不等式条件可保证闭环系统无干扰时鲁棒内稳定性和在某椭球内预先给定的有干扰时L2性能水平,该不等式通过引入辅助矩阵解除了执行器饱和对系统的影响而更易于实现且减小了保守性.采用线性矩阵不等式技术,将控制器存在的充分条件转化为凸优化问题.在此基础上设计了系统的状态反馈控制器,最后用数值仿真验证了所提出方法的可行性.     

模糊系统H∞控制器设计的LMI方法

应用LMI(线性矩阵不等式)方法,研究了T-S模糊系统H∞控制器的设计问题.首先给出了T-S模糊系统基于状态反馈H∞控制存在的两个新的充分条件.新条件不但简洁而且把模糊子系统间的相互作用表示为由子系统的系数矩阵构成的矩阵不等式.然后新条件被转化为可直接应用Matlab求解的线性矩阵不等式.最后应用线性矩阵不等式方法和Matlab,给出了T-S模糊系统H∞控制器的设计方法.     

多时变状态和控制时滞系统的绝对稳定性

研究了具有多时变状态和控制时滞的Lurie控制系统基于线性矩阵不等式(LMI)的绝对稳定性条件.首先,构造了关于Lyapunov泛函中正定矩阵和积分项系数等自由参数的LMI,获得了系统时滞无关绝对稳定条件.进一步引入自由权矩阵来表示牛顿-莱布尼兹公式中各项的相互关系,得到了系统绝对稳定的时滞相关条件.最后,通过一个实例阐述了本文方法的有效性和相比已有结果的优越性.     

考虑执行机构故障的离散系统可靠保性能控制设计

对一类离散时间线性时不变系统,研究当执行机构发生连续增益故障情况下的可靠保性能状态反馈控制律的设计问题.应用线性矩阵不等式处理方法,导出系统存在可靠保性能控制律的一个充分条件,进而用一个线性矩阵不等式的可行解给出所有可靠保性能控制律的一个参数化表示.在此基础上,通过建立和求解由一组线性矩阵不等式所表示的凸优化问题,得到最优可靠保性能控制律的设计方法.     

含状态时滞及执行器饱和不确定系统反馈镇定及L2增益分析

研究了具有控制饱和状态时滞不确定系统的L₂控制问题, 提出了状态反馈方法, 利用Lyapunov函数可获得时滞相关的线性矩阵不等式. 线性矩阵不等式条件可保证闭环系统无干扰时鲁棒内稳定性和在某椭球内预先给定的有干扰时L₂性能水平, 该不等式通过引入辅助矩阵解除了执行器饱和对系统的影响而更易于实现且减小了保守性. 采用线性矩阵不等式技术, 将控制器存在的充分条件转化为凸优化问题. 在此基础上设计了系统的状态反馈控制器, 最后用数值仿真验证了所提出方法的可行性.     

不确定广义系统的弹性H∞保性能控制

利用线性矩阵不等式(LMI)方法,研究被控对象与控制器同时存在摄动的H∞保性能控制问题.针对控制器存在加法式摄动情形,以线性矩阵不等式约束条件给出了广义系统弹性H∞保性能的充分条件,并以线性矩阵不等式的可行解给出了相应的控制器设计方法.通过求解具有线性矩阵不等式约束的凸优化问题,给出了弹性H∞最优保性能及最优H∞性能控制器的设计方法.仿真表明了方法的可行性.     

中立型一般Lurie系统绝对稳定的时滞相关准则

研究了具有时滞的中立型一般Lurie系统的绝对稳定性问题.利用Lyapunov方法给 出了系统在无限扇形角内绝对稳定的时滞相关准则,所给的判定条件是线性矩阵不等式(LMI) 形式的,可以很方便地运用Matlab工具箱求解.一个应用的例子表明与现有的一些准则相比, 本文所给的条件具有较小的保守性.     

Absolute stability of parametrically perturbed third-order systems

Consideration was given to the behavior of the third-order systems in phase space. Regularities of motion of the phase trajectories were established, and a criterion for absolute nonoscillation was obtained. For the absolutely nonoscillatory systems, the Hurwitz conditions serve as the absolute stability criterion. For the oscillatory systems, an additional Bulgakov condition was introduced to eliminate the possibility of parametric resonance. This condition which is verified on the invariant set defined using the Poincaré transform was shown to be a criterion for absolute stability of the oscillatory systems. The results obtained were used to solve the problem of absolute stability of a third-order control system with nonstationary sectorial nonlinearity.     

时滞不确定Lurie系统的鲁棒绝对稳定性准则

研究一类具有时变时滞的范敷有界结构不确定性Lurie控制系统的鲁棒绝对稳定性问题.利用Lyapunov-Krasovskii泛函方法,分别给出系统在无限扇形及有限扇形角内绝对稳定的时滞相关充分条件,所给的判定条件是线性矩阵不等式(LMI)形式的,可以很方便地运用Matlab工具葙求解.两个数值实例表明,本文所给条件是有...     

关联 Lurie 控制大系统的参数绝对稳定性

针对一类具有不确定性参数和参考输入的关联 Lurie 大系统, 研究其参数绝对稳定性的问题, 即同时考虑参数变化引起的平衡点的改变及其稳定性的问题. 首先, 基于分散状态反馈, 研究了当不确定性参数变化和参考输入改变时, 关联 Lurie 大系统参数稳定性存在条件和参数稳定区域. 其次, 给出了在该参数稳定区域中基于矩阵不等式条件的关联大系统稳定性存在的线性矩阵不等式 (LMI) 条件. 最后, 研究了多胞型关联 Lurie 大系统参数绝对稳定性存在的充分条件和求解算法. 仿真例子说明了方法的有效性.     

Influence maximization with limit cost in social network

Social networking service (SNS) applications are changing the way information spreads in online communities. As real social relationships are projected into SNS applications, word of mouth has been an important factor in the information spreading processes of those applications. By assuming each user needs a cost to accept some specific information, this paper studies the initial "seed user" selection strategy to maximize information spreading in a social network with a cost budget. The main contributions of this paper are: 1) proposing a graphic SEIR model (gSEIR) by extending the epidemic compartmental model to simulate the dynamic information spreading process between individuals in the social network; 2) proposing a formal definition for the influence maximization problem with limit cost (IMLC) in social networks, and proving that this problem can be transformed to the weighted set-cover problem (WSCP) and thus is NP-Complete; 3) providing four different greedy algorithms to solve the IMLC problem; 4) proposing a heuristic algorithm based on the method of Lagrange multipliers (HILR) for the same problem; 5) providing two parts of experiments to test the proposed models and algorithms in this paper. In the first part, we verify that gSEIR can generate similar macro-behavior as an SIR model for the information spreading process in an online community by combining the micro-behaviors of all the users in that community, and that gSEIR can also simulate the dynamic change process of the statuses of all the individuals in the corresponding social networks during the information spreading process. In the second part, by applying the simulation result from gSEIR as the prediction of information spreading in the given social network, we test the effectiveness and efficiency of all provided algorithms to solve the influence maximization problem with cost limit. The result show that the heuristic algorithm HILR is the best for the IMLC problem.     

On the absolute stability of sampled-data systems: The "Indirect control" case

A study is made of the problem of absolute stability or "Lur'e problem" in the case of a sampled-data control system containing one integrator in the loop. By the second method of Liapunov, a frequency-domain inequality is obtained which is shown to be a sufficient condition for the absolute stability of the class of systems under investigation. This inequality improves inequalities of similar type which have been obtained by means of the Popov approach.     

Minimax Optimal Control of Discrete-Time Uncertain Systems With Structured Uncertainty

Inthis paper we consider a guaranteed cost control problem fora class of uncertain discrete-time systems which contain structureduncertainties. The uncertainties are assumed to satisfy a certainsum quadratic constraint. The controller will be a minimax controllerin the sense that it minimizes the maximum value of a cost function.For a given initial condition, the minimax optimal controlleris constructed by solving a parameter dependent Riccati equation.This controller guarantees absolute stability of the closed loopsystem.     

一类不确定系统的鲁棒绝对稳定性

本文考虑一类不确定系统的绝对稳定性问题,系统的线性部分乃顶点模型的凸组合,非线性部分是一个非线性扇区如通常绝对稳定性问题中那样。我们将给出一个类似的圆判据,它说,所有顶点或边系统的某些频域条件可保证整个不确定系统是绝对稳定的。由于边系统仅含单参数,这样就大大地降低了原问题的计算复杂性。     

On stability of delayed cellular neural networks with sigmoid output functions

In this paper a sufficient condition is presented to ensure the complete stability of delayed CNNs. Such a condition establishes a relation between the time delay and the parameters of the networks. Specially, for a given output function f(x) = tanh(x), we address a sufficient condition to ensure absolute convergence of system state.