时滞系统稳定性分析和镇定: 一种基于Finsler引理的统一观点

从Finsler引理角度,研究时滞系统的时滞相关稳定性分析和镇定问题,发现自由权矩阵方法是该研究框架的一个特例,阐明引入乘子矩阵对分析时变时滞系统稳定性的必要性,讨论乘子矩阵结构对所得结果保守性的影响,提出一些改进的基于线性矩阵不等式的稳定性判据和镇定控制器设计算法,数值算例表明所提出方法的有效性.     

不确定时滞系统的保性能控制

基于时滞系统的一个新的指数稳定性定理,考虑了时不变不确定时滞系统的保性能控制问题.利用一种新的分析技术,通过解两个Riccati不等式和一个线性矩阵不等式得一保性能控制器,该控制器可保证闭环系统指数稳定且使系统满足一定的性能指标.与一般的不确定时滞系统保性能控制不同,所得的性能指标的上界中含有参数,可通过调整参数值的大小来使性能指标达到最优.所得Riccati不等式中含有时滞,因此该判据是时滞相关的.数值算例证明了该方法的适用性.     

时变时滞与切换有向通信拓扑协议下线性多智能体系统一致性的平均驻留时间条件

研究时变时滞与切换有向通信拓扑协议下高阶连续时间线性多智能体系统的一致性问题. 利用一个线性变换将该问题等价转化为一个切换时滞系统的稳定性问题. 假定出现的每一个通信拓扑都是可一致的, 借助时滞切换系统稳定性的平均驻留时间方法, 以线性矩阵不等式(LMIs) 形式给出多智能体系统达到全局一致的充分条件. 数值实例验证了结果的正确性.

     

带有非线性扰动的时变时滞系统的稳定性准则

研究了带有非线性扰动的时变时滞系统的稳定性问题.基于时滞分割方法,提出了保守性更小的系统稳定性分析准则.利用一个自由参数将时滞区间分割为2个子区间,进而构造了含有时滞分割点状态信息和3重积分项的Lyapunov-Krasovskii泛函,并采用自由矩阵积分不等式界定泛函导数中的交叉项.基于Lyapunov稳定性定理,得到了以线性矩阵不等式描述的时滞相关型稳定性准则.数值算例表明该稳定性准则能够得到更大的时滞上界,与已有结果相比具有更小的保守性.     

网络系统中动态矩阵控制的稳定性条件

网络控制系统中的时滞和丢包会影响控制器的稳定性;因此,传统的动态矩阵控制器设计方法无法适应网络化环境.本文针对这一问题设计了一种改进型动态矩阵控制器.通过建立缓存器将不确定时滞转化为固定时滞;并提出了一种更新系统单位阶跃响应系数的方法,用来处理时滞对控制器的影响.采用一次性传输整个控制序列的方法,避免了丢包时需要更新控制量的问题.此外,进一步分析了该控制系统的稳定性问题,给出了考虑时滞和丢包信息的系统稳定性充分条件.最后通过实时仿真软件示范了如何确定允许的最大时滞和丢包.验证了该方法的有效性.     

具有多个时滞的积分时滞系统的稳定性分析

首先,针对具有多个时滞的积分时滞系统,建立新的基于线性矩阵不等式的稳定性条件.该条件与正整数k有关,给出$k=1$时该条件与现有结果间的关系.该关系表明所提出条件在$k\geqslant2$时的保守性比现有结果小;然后,基于所提出的稳定性条件,进一步研究具有参数不确定性的积分时滞系统的鲁棒稳定性问题,建立基于线性矩阵不等式的充分条件;最后,利用所提出方法,研究具有多个离散时滞和分布时滞的积分时滞系统的稳定性问题.数值算例结果表明了所提出稳定性判据的有效性.     

时滞分数阶系统PDμ控制器参数整定的图解法

针对时滞分数阶系统,讨论分数阶PDμ控制器的参数整定问题.首先,利用一个可应用于时滞分数阶系统的图解稳定性准则,固定μ值,在比例一微分平面上绘制PDμ控制器参数稳定域,并讨论不同肛值对参数稳定域形状和大小的影响.该图解稳定性准则给出的是时滞分数阶系统稳定的一个充分必要条件,所得结果没有任何保守性.然后,将该种图解法思想扩展应用于系统性能设计,给出PlY'控制器最优参数整定的图解设计方法.在稳定域内分别考虑幅值裕度、相角裕度和相对稳定度性能设计问题.最后,提出了PDμ控制器参数整定的具体算法.仿真设计算法说明该图解法简洁有效,设计灵活,为一种实用的工程设计方法.     

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.     

遥操作机器人系统的透明性鲁棒控制

针对遥操作机器人系统中由于传输通道存在时滞,导致系统不稳定和系统性能下降的问题,将系统描述成一个具有多状态时滞的状态空间模型,通过透明性分析给出控制器增益矩阵需要满足的约束条件,再利用一种基于时滞划分的Lyapunov-Krasovskii泛函法进行稳定性分析并给出稳定性条件,得到既能保证稳定性,又具备一定透明性的控制器。仿真实验结果表明了该方法的有效性。     

不确定广义跳变时滞系统的鲁棒指数稳定性

讨论不确定广义跳变时滞系统的鲁棒指数稳定性问题. 利用线性矩阵不等式(LMI)技术给出一个时滞区间依赖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. 数值例子说明本文的结果改进了已有的结论.     

New stability criteria for linear time-delay systems using complete LKF method

This paper focuses on the stability test for linear systems with time-varying delay and provides new stability conditions in terms of linear matrix inequalities (LMIs). The basic idea is the use of complete Lyapunov–Krasovskii functional (LKF) method and the derivation employs the discretisation technique and the reciprocally convex combination. The main feature of this work lies in that the present result not only leads to some improvements over existing results in the LMI framework but also is applicable for time-delay systems with unstable delay-free case. Three numerical examples are given to show the effectiveness and merits of the present result.     

线性定常时滞系统全时滞渐近稳定的充分代数判据

本文探讨了线性定常时滞系统全时滞渐近稳定性问题,并给出了简单实用的稳定性充分 代数判据.     

Sampled-data control of networked linear control systems

In this paper, the problem of synthesis and analysis for the networked control systems (NCSs) with time-driven digital controllers and event-driven holders is considered. The NCS is modelled as a sampled-data system with time-delay in its discrete-time subsystem. This model is able to capture many network-induced features, for example, time-delay and packet dropout. Moreover, the model allows different combinations of the time-driven or event-driven mode of the devices, including the samplers, the controllers and the holders. By transforming time-delay in the discrete-time subsystem into its continuous-time subsystem of the sampled-data system, we have also obtained a less conservative time-delay dependent stability result for the NCSs, using a new Lyapunov function and a relaxed condition. Some limitations of the existing literatures on network-induced time-delay and sampling period are removed in the proposed framework. Furthermore, a sampled-data control design procedure is developed for the NCSs. Linear matrix inequality approach has been employed to solve the stability and control design problems. Finally, numerical examples are included to demonstrate the effectiveness of the proposed stability result and the potential of the proposed techniques.     

Lurie滞后反馈控制系统绝对稳定的鲁棒扰动界

本文应用Lyapunov方法讨论了具有时滞反馈的 Lurie控制系统的鲁棒绝对稳定性,给出了具有一个和多个滞后反馈的Lurie控制系统的绝对 鲁棒稳定的充分条件．用本文的结论可直接计算具有时滞反馈的Lurie控制系统绝对稳定的 鲁棒扰动上界．文末给出了应用本文结论的例子．     

具有时滞的线性区间系统的鲁棒稳定性

本文给出了线性区间时滞系统鲁棒稳定性的一些结果，这些结果推广和改进了前人关于线性时滞系统鲁棒稳定性的相关结论，同时还讨论了线性区间时滞系统的稳定度，最后讨论了线性区间时滞大系统的鲁棒稳定性．     

具有时滞的线性区间系统的鲁棒稳定性

本文给出了线性区间时滞系统鲁棒稳定性的一些结果，这些结果推广和是了前人关于线性时滞系统鲁棒稳定性的相关结论，同时还讨论了线性区间时滞系统的稳定度，最后讨论了线性区间时滞大系统的鲁棒稳定性。     

Stability of PID-controlled second-order time-delay feedback systems

In the previous papers, the stability of PID-controlled first-order time-delay systems has been investigated by means of several methods, of which the Nyquist criterion, a generalization of the Hermite–Biehler Theorem, and the root location method are well known. Explicit expressions of the boundaries of the stability region, which is the set of controller parameters that give stable closed-loop systems, have been determined. From these studies, one can verify that not all plants can be made stable and then obtain the set of process parameters that allow stable closed-loop systems. With this set, one can implement the stability region of the process parameters. In a recent paper the stability conditions based on Pontryagin’s studies and valid for arbitrary-order plants have been presented. The procedure deduced for the controller parameters is exhaustive, but that deduced for the process parameters requires further mathematical evaluations, whose complexity is proportional to the number of process time constants. In the aforementioned recent paper these evaluations have been performed for a second-order time-delay plant whose transfer function has no zero. The aim of this paper is to execute these calculations for a second-order plant whose transfer function has one zero and to provide the related stability region.     

具有多个未知常时滞线性系统的时滞无关稳定性

本文针对线性时滞系统包括时滞在系统建立了时滞无关的稳定性判据，所考虑的时滞可以是多任意未知常时滞，故所得结果是对滞无关的，针对线性时滞大系统的一个说明例子比较证明了所建立的结果好于文献中存在的结果。     

Small-gain theory for stability and control of dynamical networks: A Survey

This paper provides a personal account of the small-gain theory as a tool for stability analysis, control synthesis, and robustness analysis for interconnected uncertain systems. A milestone in modern control theory is the development of a transformative stability criterion known as the classical small-gain theorem proposed by George Zames in 1966, that surpasses Lyapunov theory in that there is no need to construct Lyapunov functions for the finite-gain stability of feedback systems. Under the small-gain framework, a feedback system composed of two finite-gain stable subsystems remains finite-gain stable if the loop gain is less than one. Despite its apparent simplicity at first sight, Zames’s small-gain theorem plays a crucial role in the development of linear robust control theory. Borrowing techniques in modern nonlinear control, especially Sontag’s notion of input-to-state stability (ISS), the first generalized, nonlinear ISS small-gain theorem proposed by one of the authors in 1994 overcomes the two shortcomings of Zames’s small-gain theorem. First, the use of nonlinear gains allows to consider strongly nonlinear, interconnected systems. Second, the role of initial conditions is made explicit so that both internal Lyapunov stability and external input-output stability can be studied in a unified framework. In this survey paper, we first review early developments in the nonlinear small-gain theory for interconnected systems of various types such as continuous-time systems, discrete-time systems, hybrid systems and time-delay systems, along with applications in robust nonlinear control. Then, we describe how to obtain a network small-gain theory for large-scale dynamical networks that are comprised of more than two interacting nonlinear systems. Constructive methods for the generation of Lyapunov functions for the total network are presented as well. Finally, this paper discusses how the network/nonlinear small-gain theory can be applied to obtain innovative solutions to quantized and event-based nonlinear control problems, that are important for the development of a complete theory of controlling cyber-physical systems subject to communications and computation constraints.     

时滞线性系统时滞独立稳定的劳斯-赫维茨方法

本文研究了滞后型线性时滞系统,给出了一个完全可计算的时滞独立稳定的代数充要条件,这个条件判别的全过程仅仅只需要计算二次劳斯表和一次赫维茨行列式,并且所有运算均在实数域中,具有简单性和实用性。