不确定时滞离散非线性系统的鲁棒耗散滤波

研究了一类带参数不确定性和非线性动态的离散时滞系统的鲁棒耗散滤波问题.所给系统中的不确定项是时变未知且范数有界.基于Lyapunov稳定性方法,先对参数已知而带有非线性动态的时滞离散系统,给出渐近稳定判据,然后讨论鲁棒耗散滤波器的存在条件及设计方法.在此基础上进一步考虑参数不确定性情形,将鲁棒耗散滤波器问题转化为参数确定的情况.从而将鲁棒耗散滤波器的设计问题转换为线性矩阵不等式的求解问题.最后给出仿真例子验证所得结果的有效性.     

时变时滞离散广义Markov 跳变系统的鲁棒稳定性

研究一类具有区间时变时滞的离散不确定广义Markov跳变系统的时滞相关鲁棒稳定性问题.通过将Jensen不等式与一个新的定界不等式相结合,得到了一个新的稳定性判据,该判据中仅含有Lyapunov变量,具有较小的计算负担.进而,基于凸组合方法得到了另一个新的稳定性判据,该判据引入了一些自由矩阵变量,具有较小的保守性.数值算例表明了所提出方法的有效性.     

带饱和执行器的不确定时滞系统的 鲁棒控制

研究了一类具有饱和执行器约束的不确定时滞系统时滞依赖型无记忆鲁棒控制问题 .所考虑的时滞系统包括时变未知但有界的不确定参数以及状态和控制的时滞项 .文中应用了 Lyapunov定理以及线性矩阵不等式 ( LMI)方法来研究该系统的分析和综合问题 ,导出了一个新的鲁棒可镇定判据和相应的无记忆鲁棒镇定控制律设计方法 .所得的基于一组LMIs的结果是与时滞相关的     

带饱和执行器的不确定时滞系统的鲁棒控制

研究了一类具有饱和执行器约束的不确定时滞系统时滞依赖型无记忆鲁棒控制问 题.所考虑的时滞系统包括时变未知但有界的不确定参数以及状态和控制的时滞项.文中应 用了Lyapunov定理以及线性矩阵不等式(LMI)方法来研究该系统的分析和综合问题,导出 了一个新的鲁棒可镇定判据和相应的无记忆鲁棒镇定控制律设计方法.所得的基于一组 LMIs的结果是与时滞相关的.     

时滞的不确定奇异摄动系统鲁棒稳定性研究

研究了带离散时滞和分布时滞的不确定奇异摄动系统的鲁棒稳定问题.首先采用广义系统模型方法,将所研究的系统转化为与之等价的广义系统;然后提出对应的Lyapunov-Krasovskii泛函,得到了时滞相关的鲁棒稳定性判据,并在此基础上给出了鲁棒控制器设计,结论以矩阵不等式形式给出;最后仿真算例说明了方法的有效性.     

离散多时滞系统的时滞相关鲁棒稳定性分析

研究了具有凸多面体不确定性的离散多时滞系统鲁棒稳定性问题．通过引入一种新的二次型的有限和不等式,采用参数依赖型Lyapunov泛函,导出了适用于具有凸多面体不确定性离散时滞系统的一个新的时滞相关稳定性条件．该方法不需要进行系统模型变换即可得到时滞相关的结果,和已有文献相比,所得结果具有更小的保守性．数值例子说明了该方法的有效性．     

不确定离散模糊时滞系统的时滞相关H∞控制

研究了不确定离散T-S模糊时滞系统的稳定性分析与H∞控制问题．通过构造适当的Lyapunov泛函,给出了系统的时滞相关稳定新判据．进而利用线性矩阵不等式方法,研究了H∞模糊状态反馈控制器存在的充分条件,并提出控制器优化设计的迭代算法．     

不确定离散模糊时滞系统的时滞相关H∞控制

研究了不确定离散T-S模糊时滞系统的稳定性分析与H∞控制问题．通过构造适当的Lyapunov泛函,给出了系统的时滞相关稳定新判据．进而利用线性矩阵不等式方法,研究了H∞模糊状态反馈控制器存在的充分条件,并提出控制器优化设计的迭代算法．     

不确定时滞Lur''''e型控制系统与时滞相关的绝对稳定性(英文)

研究了一类参数不确定的具有多个时滞的Lur'e型控制系统与时滞相关绝对稳定性问题.通过将原系统变换为等价的奇异系统,利用Moon不等式放大向量积,构造出一个新的Lya-punov-Krasovskii泛函.并由此基于线性矩阵不等式,得到了系统与时滞相关绝对稳定的充分条件.这些充分条件无须预调任何参数矩阵,可以直接运用Matlab软件中LMI工具箱求解.数值例子表明,与现有结果相比,本文结果较大地改进了保证不确定时滞Lur'e型控制系统绝对稳定的时滞界.     

不确定时滞Lurie型控制系统与时滞相关的绝对稳定性

研究了一类参数不确定的具有多个时滞的Lur′e型控制系统与时滞相关绝对稳定性问题.通过将原系统变换为等价的奇异系统,利用Moon不等式放大向量积,构造出一个新的Lyapunov-Krasovskii泛函.并由此基于线性矩阵不等式,得到了系统与时滞相关绝对稳定的充分条件.这些充分条件无须预调任何参数矩阵,可以直接运用Matlab软件中LMI工具箱求解.数值例子表明,与现有结果相比,本文结果较大地改进了保证不确定时滞Lur′e型控制系统绝对稳定的时滞界.     

不确定多重状态时滞离散系统的LMI鲁棒稳定条件

研究了具有多重状态时滞的凸多面体不确定离散系统的鲁棒稳定性分析问题．基于参数依赖的李亚普诺夫稳定性和线性矩阵不等式推导出使得时滞鲁棒稳定系统鲁棒稳定的充分条件．应用此条件，通过测试一组线性矩阵不等式的可解性即可达到判定系统的鲁棒稳定性的目的．因为使用了参数依赖的李亚普诺夫稳定性思想，此鲁棒稳定条件比基于二次稳定概念的稳定条件的保守性更小．算例验证了结果．     

LMI-based robust control of uncertain discrete-time piecewise affine systems

The main contribution of this paper is to present stability synthesis results for discrete-time piecewise affine (PWA) systems with polytopic time-varying uncertainties and for discrete-time PWA systems with norm-bounded uncertainties respectively. The basic idea of the proposed approaches is to construct piecewise-quadratic (PWQ) Lyapunov functions to guarantee the stability of the closed-loop systems. The partition information of the PWA systems is taken into account and each polytopic operating region is outer approximated by an ellipsoid, then sufficient conditions for the robust stabilization are derived and expressed as a set of linear matrix inequalities (LMIs). Two examples are given to illustrate the proposed theoretical results.     

凸多面体不确定系统的符号稳定性分析

针对一类凸多面体描述的连续线性不确定系统研究其符号稳定性条件,从而从符号稳定的角度探索一种新的不确定系统鲁棒控制器设计方法.在矩阵符号稳定定义和必要条件的基础上,给出了矩阵集合符号稳定的定义和完整同源稳定符号型集合的概念,得到了凸多面体不确定系统符号稳定的充分必要条件.进一步分析了符号稳定凸多面体不确定系统的特征根分布与主对角线元素的关系,提出了基于符号稳定的不确定系统状态反馈镇定控制综合方法.相比于基于Lyapunov稳定性理论的不确定系统鲁棒控制方法,本文所提方法避免了求解线性矩阵不等式,并且更符合工程设计的习惯.通过一类三轴稳定卫星姿态控制问题的算例和仿真验证了所提方法的有效性.     

不确定系统混合H2/H∞鲁棒控制的直接迭代LMI方法

设计多胞型不确定系统的控制器时,引入附加变量能够减小设计保守性,但这会使线性矩阵不等式(LMI)的维数大大增加,控制器难以求解.本文阐述了一种基于直接迭代线性矩阵不等式(DILMI)方法的混合H2/H∞鲁棒控制方法.首先借助于仿射二次稳定理论将整个多胞型不确定集合的稳定性问题转化为该集合各顶点的稳定性问题.利用参数依赖Lyapunov方法,给出了一个保证系统鲁棒稳定,并满足混合H2/H∞性能指标的充分条件.随后采用DILMI算法实现了Lyapunov变量和控制增益的解耦,无需引入附加变量就能够求解充分条件中的非凸优化问题.最后,关于F-16多胞型模型的飞行仿真验证了该方法的有效性.     

基于多面体描述系统的鲁棒非线性预测控制

针对一类具有持续有界扰动的离散时间非线性系统, 提出一种基于多面体描述系统的鲁棒非线性模型预测控制策略. 首先利用泰勒级数构造多面体描述系统包裹原系统. 其次, 对该多面体描述系统构造鲁棒终端不变集和仿射输入型预测控制律. 进一步, 利用离散系统的输入状态实际稳定性(Input-to-state practical stability, ISpS)概念证明了闭环系统的鲁棒稳定性. 最后, 通过仿真验证了本结果的有效性.     

Stability analysis and design of nonlinear sampled‐data systems under aperiodic samplings

In this paper, the problem of exponential stability analysis and the design of sampled‐data nonlinear systems have been studied using a polytopic linear parameter‐varying approach. By means of modeling a new double‐layer polytopic formulation for nonlinear sampled‐data systems, a modified form of piecewise continuous Lyapunov‐Krasovskii functional is proposed. This approach provides less conservative robust exponential stability conditions by using Wirtinger's inequality in terms of linear matrix inequalities. The distances between the real continuous parameters of the plant and the measured parameters of the controller are modeled by convex sets, and the analysis/design conditions are given at the vertices of some hyper‐rectangles. In order to get tractable linear matrix inequality conditions for the stabilization problem, we performed relaxation by introducing a slack variable matrix. Under the new stability criteria, an approach is introduced to synthesize a sampled‐data polytopic linear parameter‐varying controller considering some constraints on the location of the closed‐loop poles in the presence of uncertainties on the varying parameters. It is shown that the proposed controller guarantees the exponential stability of the closed‐loop system for aperiodic sampling periods smaller than a known value, ie, maximum allowable sampling period. Finally, the effectiveness of the proposed approach is verified and compared with some state‐of‐the‐art existing approaches through numerical simulations.     

Robust control of state delayed systems with polytopic type uncertainties via parameter-dependent Lyapunov functionals

This paper considers the problem of robust stability and robust stabilization for linear systems with a constant time-delay in the state and subject to real convex polytopic uncertainty. First of all, for robust stability problem, we exploit new matrix inequalities characterization of delay-dependent quadratic stability results, demonstrate that it allows the use of parameter-dependent Lyapunov functionals, and develop control design methods based on linear matrix inequalities (LMIs) for solving the robust control problem. Next, the problem of determining the maximum time-delay under which the system remains stable is cast into a generalized eigenvalue problem and thus solved by LMI techniques. Finally, illustrative examples are given to demonstrate the advantage of these new representations.     

Parameter dependent Lyapunov functions for discrete time systems with time varying parametric uncertainties

In this paper, we consider discrete time systems with polytopic time varying uncertainty. We look for a class of parameter dependent Lyapunov functions which are quadratic on the system state and depend in a polytopic way on the uncertain parameter. We show that extending the new discrete time stability condition proposed by de Oliveira et al. (Systems Control Lett. 36 (1999) 135.) to the case of time varying uncertainty leads to a necessary and sufficient condition for the computation of such a Lyapunov function. This allows to check asymptotic stability of the system under study. The obtained linear matrix inequalities condition can also be used to cope with the control synthesis problem.     

Output feedback controllers for systems with structured uncertainty

This paper deals with the design of compensators that provide a guaranteed level of performance, in the sense of L₂ gain, for systems with time-varying structured uncertainty. For stability, the notion of quadratic stability, using a single Lyapunov function, is used. The uncertainty is assumed to be polytopic (e.g., the uncertainty vector enters the state-space representation of the systems affinely). Earlier results in the characterization of H_∞ controllers are used to show that quadratic stability with performance is equivalent to a bi-affine problem. A set of conditions, under which the problem becomes convex, is discussed