Optimal guaranteed cost control for fuzzy descriptor systems with time-varying delay

Based on the delay-independent rule, the problem of optimal guaranteed cost control for a class of Takagi-Sugeno （T-S） fuzzy descriptor systems with time-varying delay is studied. A linear quadratic cost function is considered as the performance index of the closed-loop system. Sufficient conditions for the existence of guaranteed cost controllers via state feedback are given in terms of linear matrix inequalities （LMIs）, and the design of an optimal guaranteed cost controller can be reduced to a convex optimization problem. It is shown that the designed controller not only guarantees the asymptotic stability of the closed-loop fuzzy descriptor delay system, but also provides an optimized upper bound of the guaranteed cost. At last, a numerical example is given to illustrate the effectiveness of the proposed method and the perfect performance of the optimal guaranteed cost controller.

Robust reliable guaranteed cost control for uncertain singular systems with time-delay

The robust reliable guaranteed cost control for uncertain singular delay systems with actuator failures and a given quadratic cost function is studied. The system under consideration involves constant time-delay and norm-bounded parameter uncertainties. The purpose is to design state feedback controllers which can tolerate actuator failure, such that the closed-loop system is stable, and the specified cost function has an upper bound for all admissible uncertainties. The sufficient conditions for the solvability of this problem are obtained by a linear matrix inequality （LMI） method. Furthermore, a numerical example is given to demonstrate the applicability of the proposed approach.

Non-fragile guaranteed cost control of discrete-time fuzzy bilinear system

This paper focuses on the problem of non-fragile guaranteed cost control for a class of T-S discrete-time fuzzy bilinear systems（DFBS）.Based on the parallel distributed compensation（PDC） approach,the sufficient conditions are derived such that the closed-loop system is asymptotically stable and the cost function value is no more than a certain upper bound in the presence of the additive controller gain perturbations.The non-fragile guaranteed cost controller can be obtained by solving a set of bilinear matrix inequalities（BMIs）.The Van de Vusse model is utilized to demonstrate the validity and effectiveness of the proposed approach.

Optimal guaranteed cost control for an uncertain discrete T-S fuzzy system with time-delay

This paper considers the guaranteed cost control problem for a class of uncertain discrete T-S fuzzy systems with time delay and a given quadratic cost function. Sufficient conditions for the existence of such controllers are derived based on the linear matrix inequalities （LMI） approach by constructing a specific nonquadratic Lyapunov-Krasovskii functional and a nonlinear PDC-like control law. A convex optimization problem is also formulated to select the optimal guaranteed cost controller that minimizes the upper bound of the closed-loop cost function. Finally, numerical examples are presented to demonstrate the effectiveness of the proposed approaches.

Delay-dependent guaranteed cost control for uncertain discrete-time Markovian jump linear systems with mode-dependent time-delays

In this paper,the problem of guaranteed cost control for a class of uncertain discrete-time Markovian jump linear systems with mode-dependent time-delays and a given quadratic cost function are investigated. Attention is focused on designing a memoryless state feedback control law such that the closed-loop system is robust stochastically stable and the closed-loop cost function value is not more than a specified upper bound,for all admissible uncertainties. The key features of the approach include the introduction of a new type of suitable stochastic Lyapunov functional and free weighting matrices techniques. Sufficient conditions for the existence of such controller are obtained in terms of a set of linear matrix inequalities. A numerical example is given to illustrate the less conservatism of the proposed techniques.

基于多目标函数的避洪转移安置方案优化

针对目前避洪转移方案仅考虑时间或距离成本最优导致部分安置点人数分配不合理的问题,从“安全第一、就近就便、平灾结合、利于管理”的避洪转移安置方案基本要求出发,首先对安置点的适用性、分布合理性及容量大小3个方面进行分析,依据“时间、距离、适宜度和安置容量”四因素初步筛选合适的安置点。然后通过路权函数建立避洪转移时间成本矩阵,以转移时间成本和安置点的优化分配为多目标函数确定避洪转移安置点的最优分配方案。最后以TOPSIS评价方法对避洪转移安置点分配的单目标方案与多目标方案进行对比分析。结果表明:多目标方案的相对接近度大于单目标方案,基于多目标函数确定的避洪转移安置分配方案更加合理。

Non-fragile guaranteed cost control for uncertain neutral large-scale interconnected systems

This paper focuses on the problem of non-fragile decentralized guaranteed cost control for uncertain neutral large-scale interconnected systems with time-varying delays in state,control input and interconnections.A novel scheme,viewing the interconnections with time-varying delays as effective information but not disturbances,is developed.Based on Lyapunov stability theory,using various techniques of decomposing and magnifying matrices,a design method of the non-fragile decentralized guaranteed cost controller for unperturbed neutral large-scale interconnected systems is proposed and the guaranteed cost is presented.The further results are derived for the uncertain case from the criterion of unperturbed neutral large-scale interconnected systems.Finally,an illustrative example shows that the results are significantly better than the existing results in the literatures.

Delay-dependent guaranteed cost control for uncertain systems with both state and input delays

This paper considers the guaranteed cost control problem for a class of uncertain linear systems with both state and input delays. By representing the time-delay system in the descriptor system form and using a recent result on bounding of cross products of vectors, we obtain new delay-dependent sufficient conditions for the existence of the guaranteed cost controller in terms of linear matrix inequalities. Two examples are presented which show the effectiveness of our approach.

基于LMI的不确定随机时滞系统输出反馈保性能控制

针对一类范数有界的随机时滞系统,研究在一定性能指标下的保性能控制问题。本文为获得能够实现系统保性能控制的最优输出反馈控制器,采用Lyapunov稳定性理论与LMI技术相结合的方法,将保性能控制问题转化为LMIs约束下的可行解问题。提出的控制器设计方案能够实现系统是依概率全局渐近稳定的,同时满足对系统性能指标的要求。此外,通过数值算例说明所提出控制方案的可行性。

基于要素分析的国家历史文化名城格局中心性研究

基于全国119座国家历史文化名城的空间格局,在格局中心与行政归属、交通可达与空间破碎度、时间成本矩阵与最优市场选择等关键性指标和分析方法上,对行政条件、交通条件、市场条件影响下的国家历史文化名城中心性、中心职能、中心格局、服务市场范围进行解释和分析。结果发现:国家历史文化名城受制于全国范围内多中心分布和县级、地级的行政归属,其发展格局呈现大范围离散和小范围集聚版块的景观形态,地级名城格局中心向东部地区稍有偏离,县级名城格局中心向西部地区明显偏离。交通条件影响下的国家历史文化名城格局呈大范围集聚和局部离散的面状形态,格局中心虽然也因时间距离差异出现东部偏离、南部偏离的特征,但偏离的波动情况远远低于行政条件的影响水平。市场原则影响下的国家历史文化名城格局发展呈现错综复杂的网状形态和地域相关的区位特征,格局中心或区域中心性在全国不同地区表现出不同的地域特征。名城格局中心在不同要素下分布的不同特点是名城发展中区域自发集聚与行政手段管理调控、基础设施建设引导等相互博弈的结果。行政职能下降,交通职能、市场职能增长是未来的发展趋势。

不确定离散切换系统鲁棒保性能控制器设计

对一类具有范数有界参数不确定性的离散切换系统和一个二次型性能指标,研究其鲁棒保性能状态反馈控制器的设计问题.利用切换Lyapunov函数方法和线性矩阵不等式技术,给出了鲁棒保性能控制器存在的一个充分条件,并获得了控制器的一个参数化表示.在此基础上,将次优保性能控制器的设计问题转化为基于线性矩阵不等式约束下的凸优化问题.数值例子说明了所提设计方法的有效性.

一类中立型时滞系统的时滞依赖保性能控制

研究了一类含有不确定参数和非线性扰动的中立型时滞系统的时滞依赖保性能控制问题,所设计的控制器对于所允许的的参数不确定性和时滞,能保证闭环系统渐近稳定且闭环的性能函数值不超过给定上界.最后通过解优化问题得到性能指标的最小上界.数值例子证明了所设计控制器的有效性和较小保守性.

不确定非线性广义时滞系统的保性能控制

针对扰动满足Lipschitz条件的一类非线性广义时滞系统,研究了保性能控制器的设计问题.应用线性矩阵不等式方法,给出了系统保性能控制器存在的充分条件;并在这些条件可解时,给出了保性能控制器的表达式.最后通过数值算例说明了所给方法的有效性.

基于LMI的奇异不确定时滞系统鲁棒保成本控制

针对一类奇异不确定时滞系统的鲁棒保成本控制,假定其中的不确定性是范数有界,采用基于线性矩阵不等式(LMI)和构造适当的LYAPUNOV泛函相结合的方法,给出了系统的鲁棒保成本状态反馈控制器存在的条件。通过求解相应的线性矩阵不等式就可得到鲁棒保成本控制,所设计的保成本控制器对所有容许的不确定性不仅使得相应的闭环系统达到二次稳定,也能保证闭环成本函数不超过一个确定的界。通过数值算例及仿真验证了所给方法的有效性。

具有时滞依赖的不确定系统鲁棒H_∞保代价控制

针对一类含有时滞依赖的不确定线性系统,研究了具有鲁棒H∞性能的保代价控制器的设计。假定其中的不确定性是范数有界的和系统的状态是完全可测的,采用基于线性矩阵不等式和构造适当的Lyapunov泛函相结合的方法,给出了一种鲁棒H∞状态反馈保代价控制器的设计,仅通过求解相应的线性矩阵不等式就可得到鲁棒H∞状态反馈保代价控制器,所设计的保代价控制器对所有容许的不确定性不仅使相应的闭环系统渐进稳定,而且能保证闭环系统满足一定的鲁棒H∞保代价性能指标,达到抑制干扰的效果。最后,用数值算例及仿真结果验证了所给方法的可解性和有效性。

不确定离散系统的最优保性能控制

对一类具有范数有界时变参数不确定性的离散时间线性系统和一个二次型性能指标，研究其最优保性能状态反馈控制律的设计问题．通过采用线性矩阵不等式方法，导出了存在保性能控制律的一个充分必要条件，进而，证明了该条件等价于一个线性矩阵不等式的可解性问题，并用这组线性矩阵不等式的可行解给出了保性能控制律的一个参数化表示．在此基础上，通过建立并求解一个凸优化问题，给出了最优保性能控制律的设计方法．

基于LMI的不确定时滞切换广义系统的保成本控制

研究了一类具有状态时滞不确定性的切换广义系统在任意切换策略下的二次稳定保成本控制问题。利用线性矩阵不等式(linear matrix inequality,LMI)技术,给出了状态反馈保成本控制器存在的充分条件,使得所研究的时滞不确定切换广义系统是可行的,并满足相应的性能指标。进一步将保成本控制器的设计问题转化为线性矩阵不等式的可行解问题。数值仿真算例说明了该方法的有效性。

双分辨率集合卡尔曼滤波同化方案与模拟试验

对于高分辨率中尺度模式集合卡尔曼滤波实际应用的困难是集合预报会耗费大量的时间,而双分辨率集合卡尔曼滤波是由一组低分辨率样本提供同化所需的背景误差协方差矩阵,这种方法可以减少集合预报的时间。为了检验其有效性,利用模拟资料,与标准高分辨率集合卡尔曼滤波方法比较。结果表明:在第一个同化时次,两者对500 hPa水平风场和扰动位温场的分析增量场均与真实增量场的高低值中心位置一致,且结构与真实增量场接近,前者(高分辨率集合卡尔曼滤波)的增量值比后者(双分辨率集合卡尔曼滤波)的增量值更接近真实情况。在连续的预报—同化循环试验中,随着同化次数的增加,两种方法分析变量的均方根误差总体上都是下降的,均表现了较好的同化能力,但后者与前者相比仍存在一定的差距;而在相同的运行环境下,后者的运行时间仅是前者的1/6。

具有控制约束的不确定离散系统最优保性能控制

对一类具有范数有界时变参数不确定性和控制输入约束的离散时间线性系统,采用线性矩阵不等式处理方法,导出了保性能控制律存在的条件,证明了该条件等价于一组线性矩阵不等式的可行性问题,并用这组线性矩阵不等式的可行解给出了保性能控制律的一个参数化表示。进而,通过建立并求解一个凸优化问题,给出了具有控制约束的不确定离散系统最优保性能控制律设计方法。

变时滞不确定控制系统的保性能控制器设计

本文讨论了一类具有时变时滞不确定系统的无记忆状态反馈保性能控制器设计问题.系统的不确定性具有范数有界形式,时滞是时变函数甚至可以是无界函数,并且设计的控制器包含状态时滞.推导出了保性能控制器存在的充分条件.利用先进的线性矩阵不等式(LMIs)技术给出了保性能控制器的控制参数和保性能值,这些条件与时滞的导数有关.最后给出一个无界时滞的仿真示例说明本文方法的有效性.