Enhanced H∞ Filtering for Continuous-time State-delayed Systems

The H∞ filtering problem for continuous-time polytopic uncertain time-delay systems is investigated. Attention is focused on the design of full-order filters guaranteeing a prescribed H∞ attenuation level for the filtering error system. First, a simple alternative proof is given for an improved linear matrix inequality （LMI） representation of H∞ performance. Then, based on the performance criterion which keeps Lyapunov matrices out of the product of system dynamic matrices, a suficient condition for the existence of robust estimators is formulated in terms of LMIs, and the corresponding filter design is cast into a convex optimization problem which can be effciently handled by using standard numerical algorithms. It is shown that the proposed design strategy allows the use of parameter-dependent Lyapunov functions and hence it is less conservative than some earlier results. A numerical example is employed to demonstrate the feasibility and advantage of the proposed design.     

Enhanced LMI Representations for H2 Performance of Polytopic Uncertain Systems： Continuous-time Case

Based on two recent results, several new criteria of H2 performance for continuous-time linear systems are established by introducing two slack matrices. When used hi robust analysis of systems with polytopic uncertainties, they can reduce conservatism inherent in the earlier quadratic method and the established parameter-dependent Lyapunov function approach. Two numerical examples are included to illustrate the feasibility and advantage of the proposed representations.     

多时滞不确定系统的H_∞反馈控制

研究了具有多个输入时滞的不确定系统H∞控制问题。本文同时考虑了系统的输入时滞和不确定性,基于Lyapunov稳定性理论,采用线性不等式方法得出了系统的H∞反馈控制器。未引入自由权矩阵和模型变换,减少了计算的复杂性。仿真结果证实了方法的有效性。     

不确定奇异系统的有限时间H_∞控制

针对一类在有限时间下的线性奇异系统,同时考虑参数不确定性和有限外部扰动影响,研究了系统基于状态反馈控制器的鲁棒H∞控制问题。首先通过构造合适的Lypunov函数,利用线性矩阵不等式方法给出了线性广义系统有限时间有界且H∞范数有界的充分条件,在此基础上讨论线性广义系统的H∞状态反馈控制,给出了控制器存在的充分条件,同时给出了控制器的具体设计方法,控制器可由线性矩阵不等式解得。最后的数值算例说明了所提出方法的可行性和有效性。     

不确定离散时滞系统的时滞相关非脆弱H_∞控制

讨论不确定离散时滞系统非脆弱控制器的设计问题.利用Lyapunov-Krasovskii稳定性理论和有限和不等式方法,获得了不确定时滞系统在非脆弱控制器作用下不仅内部渐近稳定,而且具有给定的H∞扰动抑制水平y的时滞相关有界实条件.采用迭代算法分别给出了控制器具有加法不确定性和乘法不确定性两种情况的非脆弱控制器参数的设计方法,借助于Matlab的LMI工具箱可以方便求解.数值仿真实例表明了该方法的有效性.     

一类非线性不确定时滞系统的混杂状态反馈H∞鲁棒控制

利用混杂状态反馈控制策略研究一类非线性不确定时滞系统的H∞鲁棒控制问题.假定在给定的控制器集合中有有限个备选的状态反馈控制器,并且每个单一的连续控制器都不能使系统具有鲁棒H∞性能.当控制器的增益矩阵已知时,基于单Lyapunov函数技术和凸组合条件给出控制器切换方案以确保非线性不确定时滞系统具有鲁棒H∞性能.当控制器的增益矩阵未知时,使用多Lyapunov函数技术得到了问题可解的另一个充分条件,同时还给出了混杂状态反馈H∞控制器的设计.     

变时滞不确定奇异系统的输出反馈H_∞控制(英文)

针对同时含有变时滞和参数不确定性的奇异系统,研究了基于静态输出反馈的鲁棒H∞控制问题。采用Lya-punov泛函方法,给出了奇异系统时滞依赖渐近稳定且具有H∞范数界γ充分条件;利用含等式约束的线性矩阵不等式(LMI)方法,给出了此类系统存在输出反馈的时滞依赖充分条件,该条件等价于严格线性矩阵不等式可解性问题,利用严格LMI的可行解,得到控制器矩阵的参数化表示。与已有结果相比,此鲁棒控制器的渐近稳定性条件宽松,克服了时滞奇异系统稳定性问题条件中的等式约束。数值算例说明了该方法的有效性。     

一类关联时滞组合系统的H_∞滤波

针对当输入噪声为有限能量信号时的渐近稳定的线性滤波器的设计问题,基于Lyapunov稳定性理论,结合线性矩阵不等式技术,提出了一类关联时滞组合系统的H_∞滤波器的设计方案,并利用有界实引理给出了滤波器存在的一个充分条件。为了使得滤波器具有良好的稳态性能,考虑了LMI的优化问题。并将滤波器的设计问题转化为具有线性矩阵不等式约束的凸优化求解问题。通过求解一组LMI,可以得到最优滤波器。     

基于切换模糊模型和分段Lyapunov函数的T-S模糊系统时滞依赖H∞控制

研究了离散时滞T-S模糊系统的H无穷控制问题. 首先, T-S模糊系统被转换成等价的切换模糊系统, 基于分段Lyapunov函数, 给出了该系统带有H无穷性能的时滞依赖稳定化控制方法. 所得结论可以用一组线性矩阵不等式表示. 由于考虑了子系统间的相互关系, 因此所得结论较以往结果具有更小的保守性. 最后, 仿真例子说明了所提方法的有效性.     

Adaptive H_∞ Synchronization of Master-slave Systems with Mixed Time-varying Delays and Nonlinear Perturbations： An LMI Approach

This paper proposes an adaptive synchronization problem for the master and slave structure of linear systems with nonlinear perturbations and mixed time-varying delays comprising different discrete and distributed time delays. Using an appropriate Lyapunov-Krasovskii functional, some delay-dependent sufficient conditions and an adaptation law including the master-slave parameters are established for designing a delayed synchronization law in terms of linear matrix inequalities(LMIs). The time-varying controller guarantees the H _∞ synchronization of the two coupled master and slave systems regardless of their initial states. Particularly, it is shown that the synchronization speed can be controlled by adjusting the updated gain of the synchronization signal. Two numerical examples are given to demonstrate the effectiveness of the method.     

带有无穷分布时滞的不确定系统的鲁棒H∞滤波器设计

针对一类在系统的状态方程与可测输出中都包含有非线性无穷分布时滞的参数不确定系统,提出一种新颖的鲁棒H∞滤波器的设计方法.设计的鲁棒H∞滤波器可以保证对于带有时变且范数有界的参数不确定性的滤波误差系统是渐近稳定的,并且满足所给定的H∞性能指标.鲁棒H∞滤波器可以通过线性矩阵不等式方法获得.通过一个数值的例子验证了该方法的有效性.     

一类非线性时滞系统的H_∞鲁棒故障检测滤波器设计

研究一类受时变时滞影响的非线性不确定系统H∞鲁棒故障检测滤波器设计问题.首先采用基于观测器的故障检测滤波器作为残差产生器,将故障检测滤波器设计归结为H∞滤波问题;然后应用Lyapunov-Krasovskii方法,推导并证明了问题可解的依赖时滞的充分条件,通过求解线性矩阵不等式得到了观测器增益矩阵的解;最后通过算例验证了所提出方法的有效性.     

Delay-dependent Non-fragile H∞ Filtering for Uncertain Fuzzy Systems Based on a Switching Fuzzy Model and Piecewise Lyapunov Function

This paper is concerned with the non-fragile H∞ filter design problem for uncertain discrete-time Takagi-Sugeno (T-S) fuzzy systems with time delay. To begin with, the T-S fuzzy system is transformed to an equivalent switching fuzzy system. Then, based on the piecewise Lyapunov function and matrix decoupling technique, a new delay-dependent non-fragile H∞ filtering method is proposed for the switching fuzzy system. The proposed condition is less conservative than the previous results. Since only a set of LMIs is involved, the filter parameters can be solved directly. Finally, a design example is provided to illustrate the validity of the proposed method.     

基于LMI的广义时滞系统的鲁棒H_∞控制

针对一类广义时滞系统,假定系统的状态是完全可测的,基于线性矩阵不等式(LMI),通过构造Lyapunov泛函,给出了一种鲁捧H∞状态反馈控制器的设计,仅通过求解栩应的线性矩阵不等式就可得到鲁棒H∞状态反馈控制器。并证明了该方法不仪使得相应的闭环系统渐近稳定,又能保证闭环系统从扰动到受控输出之间传递函数的H∞范数不大于给定的指标值。用数值算例验证了所给方法的有效性。     

一类网络控制系统的鲁棒H∞状态反馈控制器设计

针对一类具有状态时变时滞且模型中具有参数摄动的网络控制系统,通过构造输入时滞、添加自由矩阵的技巧,利用Lyapunov 泛函和线性矩阵不等式工具,得到闭环系统鲁棒渐近稳定且满足给定H∞扰动抑制水平γ的时滞条件,并给出系统的鲁棒H∞状态反馈控制器的设计方法。所用方法适合时滞以任何速度变化的系统,且不需要知道时滞的导数信息。最后用实例仿真证明了结论的有效性。     

Improved Parameter-dependent H∞ Filtering for Polytopic Delta Operator Systems

The problem of H∞ filtering for polytopic Delta operator linear systems is investigated. An improved H∞ performance criterion is presented based on the bounded real lemma. Upon the improved performance criterion, a sufficient condition for the existence of parameter-dependent H∞ filtering is derived in terms of linear matrix inequalities. The designed filter can be obtained from the solution of a convex optimization problem. The filter design makes full use of the parameter-dependent approach, which leads to a less conservative result than conventional design methods. A numerical example is given to illustrate the effectiveness of the proposed approach.     

Peak-to-Peak Gain Minimization for Uncertain Linear Discrete Systems： A Matrix Inequality Approach

A matrix inequality approach to peak-to-peak gain minimization for a class of uncertain linear discrete systems is studied. We minimize the ＊-norm, which is the best upper bound on the induced L∞ norm obtained by bounding the reachable set with inescapable ellipsoids, instead of minimizing the induced L∞ norm directly. Based on this idea, the problems of robust peak-to-peak gain minimization and controller synthesis are reduced to solving the feasibility problems of a set of matrix inequalities. A numerical example is used to demonstrate the feasibility and effectiveness of the presented method.     

LPV重复过程的H_∞滤波新方法

将时滞线性参数变化(LPV)思想应用于重复过程中,研究了其H∞滤波问题。基于参数依赖Lyapunov函数方法推出了该重复过程的稳定性和滤波器设计的充分条件。通过投影定理引入两个附加矩阵,解除了重复过程矩阵和依赖于参数的Lyapunov函数矩阵之间的耦合,使得到的条件便于求解。仿真实例证实了该设计方法的有效性。     

不确定广义系统的弹性H_∞控制

现有的鲁棒控制器设计方法(如H2,H∞和μ等综合方法),当控制器存在参数摄动时,其维持闭环系统稳定性的能力很弱。针对一类不确定广义系统,研究了控制器增益具有乘法式摄动时的H∞控制。基于线性矩阵不等式(LMI)方法,给出了广义系统具有H∞性能的充要条件及相应的控制器的设计方案,并给出了弹性H∞控制优化问题的求解方法。仿真算例表明了该方法的可行性。     

网络控制系统H∞鲁棒控制器设计

针对存在不确定时延的网络控制系统, 将未知扰动和建模误差转换为满足给定约束的矩阵, 建立具有参数不确定性的网络控制系统模型。基于Lyapunov稳定性理论证明控制系统渐近稳定, 结合线性矩阵不等式完成H∞鲁棒控制器设计。通过仿真实验, 比较在不同时延条件下系统的状态响应曲线, 结果证明所设计的H∞鲁棒控制器可以解决系统中存在不确定建模误差、干扰和时延等问题, 具有一定的鲁棒性。