基于周期动态事件触发的网络化切换系统的分析与控制

针对网络化系统研究具有模态依赖平均驻留时间(MDADT)和异步的线性切换系统的周期动态事件触发$H_\infty$控制.与已有切换系统事件触发方式不同,周期动态事件触发引入动态事件触发参数,且具有最小的事件触发间隔下界,在降低数据发送数量的同时,能够有效避免奇诺行为;利用MDADT方法和多Lyapunov函数技术,给出闭环系统具有指数稳定和$H_\infty$加权性能的充分条件;在此基础上,针对周期动态事件触发机制中可能存在的异步问题,提出相应的控制器设计准则.最后,通过算例验证所得结果的优越性.     

异步时滞切换正系统的有限时间镇定

研究异步切换下时滞切换正系统的有限时间控制问题,即针对控制器切换滞后于子系统切换形成的异步现象,基于平均驻留时间切换方法对切换正系统开展有限时间镇定研究.首先,将每个正子系统运行的区间划分为子系统与控制器匹配和失配区间,并构造多余正Lyapunov-Krasovskii泛函;其次,基于有限时间稳定理论,实现平均驻留时间切换律及异步时滞切换正系统有限时间镇定控制器的联合设计,并给出连续时间和离散时间两种情形下系统有限时间镇定的充分条件;最后,通过两个仿真例子验证所提出方法的有效性.     

一类非线性切换时延系统的鲁棒稳定性

本文通过利用平均驻留时间方法,研究一类具有不确定性非线性切换时延系统的指数稳定性问题。给出非切换系统的候选李雅普诺夫函数的衰减估计分析,然后以线性矩阵不等式的形式给出使系统保持指数稳定及鲁棒指数稳定的充分条件,同时也给出了系统状态指数衰减的具体的估计形式。     

分数阶时变切换系统有限时间异步控制

针对一类时变切换系统,当考虑子系统具有分数阶(Fractional Order)特性时,提出了一种基于模型依赖平均驻留时间方法的有限时间稳定性条件及异步切换控制策略.借助Caputo分数阶导数引理和切换Lyapunov函数,利用矩阵不等式技术提出了分数阶时变切换系统有限时间稳定的充分条件.将有限时间稳定的结果进一步推广到有限时间有界的情形,利用平均驻留时间思想提出了分数阶时变切换系统有限时间有界的充分条件,基于该条件设计了系统的异步切换控制器.所给出的设计方法将系统异步切换控制问题转化为矩阵不等式组的求解问题.通过数值仿真验证了所提控制方法的有效性.     

一类非线性网络控制系统镇定的新方法

研究了一类非线性网络控制系统(Networked control systems, NCSs)的镇定问题. 在一般的网络环境中, 通过平行分布补偿技术, 将非线性NCS建模为包含一个稳定子系统和一个可能不稳定子系统的模糊时滞切换系统. 利用分段Lyapunov泛函方法和平均驻留时间方法, 得到了非线性NCS指数稳定的充分条件, 并以线性矩阵不等式(Linear matrix inequality, LMI) 形式给出了模糊控制器的设计方法. 最后通过数值例子说明了所给方法的有效性.     

离散双切换线性正系统的L1增益性能分析

离散时间双切换线性正系统是同时受到确定切换信号和Markov随机切换信号共同影响的系统。鲁棒稳定以及扰动抑制问题是研究混杂系统稳定性的重要问题,但双切换正系统的扰动抑制问题研究较少。基于此研究背景,提出了新型的切换系统——具有指数不确定性的离散时间双切换线性正系统(DDSLPS),通过构建Co-positive Lyapunov能量衰减函数,利用线性编程(LP)得到确保DDSLPS在持续驻留时间(PDT)约束下系统满足鲁棒指数几乎处处稳定(Robust-EAS)的充分条件。另外,将此方法推广到DDSLPS的L1增益分析中,得到闭环系统在鲁棒指数几乎处处稳定下满足L1性能指标x的充分条件。利用Matlab数值仿真,验证了所用方法的有效性和所得结果的正确性。     

基于模型依赖平均驻留时间的线性切换系统有限时间??∞ 控制

针对一类具有有界干扰的线性切换系统研究其有限时间鲁棒控制问题。基于模型依赖平均驻留时间,提出了系统有限时间有界且具有H∞性能指标的充分条件,与传统方法中系统具有单一平均驻留时间不同,各切换子系统具有各自的平均驻留时间,因而降低了设计的保守性。进一步,将切换系统的有限时间状态反馈控制器设计转化为具有线性矩阵不等式约束的优化问题。数值算例和仿真对比表明,所提出的方法增加了切换律设计的自由度。     

时变时滞连续切换奇异系统的一致有限时间稳定分析

讨论一类含有时变时滞的连续时间切换奇异系统的一致有限时间稳定、有限时间有界和状态反馈镇定问题. 在给定任意的切换规则下, 运用多Lyapunov 函数和平均驻留时间方法设计使得闭环系统一致有限时间稳定和有限时间有界的状态反馈控制器, 同时给出基于线性矩阵不等式表示的控制器存在的充分条件. 最后通过数值算例表明了所提出方法的合理性和有效性.

     

一类具有输入时滞的切换系统的正性镇定

研究一类含有输入时滞的切换系统正性镇定问题.通过引入增广系统,将时滞作为一个切换参数,原系统的正性镇定问题转化为增广系统异步切换下的控制问题.利用对偶系统的特性,得到增广系统在平均驻留时间切换下为正且稳定的充分条件,进而设计控制器以保证闭环系统的正性和稳定性.得到的充分条件可转化为标准的线性规划问题,利用Matlab的linprog工具箱进行求解.最后,通过仿真示例验证了所得结果的有效性.     

不确定切换奇异时滞系统鲁棒指数容许性分析

讨论一类连续时间不确定切换奇异区间时变时滞系统的鲁棒指数容许性问题. 通过定义衰减率依赖李亚普诺夫函数并利用平均驻留时间法, 给出一个时滞区间依赖充分条件保证标称系统正则、无脉冲且均方指数稳定. 同时该准则也被推广至不确定系统. 本文获得的结论为连续时间切换奇异时滞系统的基本问题提供了一个解, 即识别切换信号使得切换奇异时滞系统正则、无脉冲且均方指数稳定. 数值例子说明本文结果的有效性.     

Multiple-mode adaptive state estimator for nonlinear switched systems

This paper deals with the issue of state estimator design for nonlinear switched systems. A multiplemode adaptive estimator is proposed under mode-dependent average dwell time (MDADT) switching, and the switching signal with MDADT constraint is also obtained to guarantee the exponential stability of estimation error dynamics, where the Lipschitz constant may be unknown since it is adaptively adjusted by designing an adaptation law. Based on both Lyapunov stable theory and the feasible solution of an optimization problem with linear matrix inequality constraint, the gain matrices and switching signals are provided, respectively. The sufficient conditions of the existence of multiple-mode adaptive switched estimator are also derived. Meanwhile, the above methods are also extended to the case of the average dwell time (ADT) switching, and an algorithm is given to summarize the implementation of the proposed estimators. Finally, the effectiveness of the designed methods is illustrated by simulation examples.     

New finite-time stability conditions of linear switched singular systems with finite-time unstable subsystems

ABSTRACT

This paper addresses the finite-time stability problem of linear switched singular systems with finite-time unstable subsystems. Dynamic decomposition techniques are used to transform such systems into equivalent one that is a reduced-order switched normal systems. Based on the mode-dependent average dwell time (MDADT) switching signal, new sufficient conditions are presented to guarantee the linear switched singular systems with finite-time unstable subsystems being finite-time stability, finite-time bounded and finite-time stabilization. Finally, a numerical example is employed to verify the efficiency of the preceding method.     

Weighted H ∞ performance analysis of switched linear systems with mode-dependent average dwell time

This article is concerned with the disturbance attenuation properties of a class of switched linear systems by using a mode-dependent average dwell time (MDADT) approach. The proposed switching law is less strict than the average dwell time (ADT) switching in that each mode in the underlying system has its own ADT. By using the MDADT approach, a sufficient condition is obtained to guarantee the exponential stability with a weighted H _∞ performance for the underlying systems. A numerical example is given to show the validity and potential of the developed results on improving the disturbance attenuation performance.     

Caputo分数阶切换线性系统的指数稳定性

众所周知,与整数阶切换系统不同, Caputo分数阶切换系统的积分下界不能随子系统的切换而被更新,意味着在下界非一致的任意区间内不能直接取分数阶导数的分数阶积分.对此,本文给出了一个不等式(文中引理6)克服这一问题,并用1个数值例子进行了验证.通过这一不等式,然后分别利用多Lyapunov函数方法和模型依赖平均驻留时间(MDADT)方法,给出了Caputo分数阶切换线性系统指数稳定的条件,并利用2个数值例子进行验证.     

Stability of switched positive nonlinear systems

This paper considers the stability problem for a class of switched positive nonlinear systems (SPNSs), which includes switched positive linear systems as a special case. We derive a necessary and sufficient condition for stability of continuous‐time SPNSs defined by homogeneous and cooperative vector fields under average dwell time switching. A corresponding necessary and sufficient condition is also given for stability of discrete‐time SPNSs defined by homogeneous and order‐preserving vector fields under average dwell time switching. The stability results for switched positive linear systems, which have been studied in the literature, can be easily obtained. We also extend the results to general switched linear systems. Finally, a numerical example is provided to illustrate the effectiveness of our results. Copyright © 2015 John Wiley & Sons, Ltd.     

Stability of a class of switched stochastic nonlinear systems under asynchronous switching

The stability of a class of switched stochastic nonlinear retarded systems with asynchronous switching controller is investigated. By constructing a virtual switching signal and using the average dwell time approach incorporated with Razumikhin-type theorem, the sufficient criteria for pth moment exponential stability and global asymptotic stability in probability are given. It is shown that the stability of the asynchronous stochastic systems can be guaranteed provided that the average dwell time is sufficiently large and the mismatched time between the controller and the systems is sufficiently small. This result is then applied to a class of switched stochastic nonlinear delay systems where the controller is designed with both state and switching delays. A numerical example illustrates the effectiveness of the obtained results.     

基于模型依赖驻留时间的异步切换控制

研究在模型依赖平均驻留时间切换策略下切换线性系统的异步切换控制问题,同时考虑模型依赖的控制器滞后时间的约束问题.在实际情况下,信号传输和系统检测等原因会导致控制器的切换滞后于子系统.基于这类情况,首先将子系统运行的区间划分为子系统与控制器相匹配的区间和非匹配的区间,根据模型依赖的驻留时间策略设计出各子系统的控制器;然后,结合模型依赖的控制器滞后时间、系统参数和Lyapunov稳定条件推导出合适的驻留时间设计参数,且使得异步切换系统全局一致指数稳定;最后通过数值仿真验证了所提出方法的有效性.     

Minimum Dwell Time for Global Exponential Stability of a Class of Switched Positive Nonlinear Systems

This paper will investigate global exponential stability analysis for a class of switched positive nonlinear systems under minimum dwell time switching, whose nonlinear functions for each subsystem are constrained in a sector field by two odd symmetric piecewise linear functions and whose system matrices for each subsystem are Metzler. A class of multiple time-varying Lyapunov functions is constructed to obtain the computable sufficient conditions on the stability of such switched nonlinear systems within the framework of minimum dwell time switching. All present conditions can be solved by linear/nonlinear programming techniques. An example is provided to demonstrate the effectiveness of the proposed result.      

Stabilization of Discrete‐time Switched Systems with State Constraints Based on Mode‐Dependent Average Dwell Time

This paper considers the stabilization problem for a class of switched systems with state constraints based on mode‐dependent average dwell time (MDADT) in discrete‐time context. An improved average dwell time method is proposed, which is less conservative than the common average dwell time method. The sufficient conditions and stabilizing state feedback controllers for stabilization of discrete‐time switched systems with state constraints under MDADT switching are derived. Finally, the simulation results show that the approach designed by this paper is effective.