Passivity and global stabilization of cascaded nonlinear systems

An alternative stability analysis is presented for recent results on global stabilization of a nonlinear system in cascade with a linear system. The analysis is carried out using passivity arguments. The relationship between passivity and an important class of Lyapunov function is also presented     

基于状态观测的量化系统稳定性分析

针对基于状态观测和信号量化的线性系统,进行了稳定性分析与研究.首先对状态观测误差系统在量化作用下的渐近稳定性进行了分析,接着研究了对象系统本身在量化效应下的渐近稳定性,得到了相应的稳定性条件,同时针对对数型量化器,给出了两个系统稳定性之间的关联.最后,给出了在时变量化作用下基于状态观测的控制策略和仿真例子.     

有向切换拓扑条件下多航天器分组姿态协同控制

针对有向切换拓扑条件下多航天器分组姿态协同控制问题,提出一种基于变量代换和矩阵分解的控制方法.首先,给出分组情况下系统Laplacian矩阵特征值的性质,并对航天器姿态模型进行变量代换,将非线性系统的分组姿态协同问题转化为线性系统的分组一致问题;然后,通过分解Laplacian矩阵,将分组一致问题转化为线性切换系统的稳定性问题,从而通过Lyapunov稳定性理论进行分析,给出系统拓扑的最小驻留时间;最后,对包含两个分组的系统进行仿真,结果表明了所提出控制方法的有效性.     

Stabilization of Rössler chaotic dynamical system using fuzzy logic control algorithm

This paper proposes a fuzzy logic control algorithm (FLCA) to stabilize the Rössler chaotic dynamical system. The fuzzy logic control system is based on a Takagi-Sugeno-Kang inference engine and the stability analysis in the sense of Lyapunov is carried out using Lyapunov’s direct method. The new FLCA is formulated to offer sufficient inequality stability conditions. The asymptotic complexity of our algorithm is analyzed and proved to be lower in comparison with that of linear matrix inequality-based FLCAs. A set of simulation results illustrates the effectiveness of the proposed FLCA.     

Model Based Robust Control Law for Linear Event‐Triggered System

This paper proposes a framework to design an event‐triggered based robust control law for linear uncertain system. The robust control law is realized through both static and dynamic event‐triggering approach to reduce the computation and communication usages. Proposed control strategies ensure stability in the presence of bounded matched and mismatched system uncertainties. Derivation of event‐triggering rule with a non‐zero positive inter‐event time and corresponding stability criteria for uncertain event‐triggered system are the key contributions of this paper. The efficacy of proposed algorithm is carried out through a comparative study of simulation results.     

基于线性T-S模糊系统的自适应系统的设计和稳定性分析

提出了一种新型的模糊自适应控制器.其中系统的未知函数由线性T-S模糊系统估计, 模糊规则的后件是线性可调的.因线性T-S模糊系统较之Mamdani模糊系统具有更好的估计性 能,我们可以获得更小的跟踪误差.由于采用李亚普诺夫合成方法来设计控制器,整个闭环系统 全局稳定,所有的信号有界.对倒立摆的仿真验证了这一点.     

Dynamic predictor for systems with state and input delay: A time‐domain robust stability analysis

The robust stability of linear systems with both state and input delay in closed loop with dynamic predictor‐based controller is analyzed. The problem of time‐varying matrix uncertainty is studied in the Lyapunov‐Krasovskii framework. The complete type functional with prescribed derivative expressed in terms of the delay Lyapunov matrix associated with the nominal system is a key piece of our analysis. The robust stability conditions depend on the delay Lyapunov matrix whose computation is carried out. An illustrative example is presented.     

基于模式运动的一类复杂生产过程的状态反馈渐近稳定性

针对基于模式运动描述的一类复杂生产过程的稳定性,给出了系统稳定的定义,提出了分析与判断系统渐近稳定的方法和充分条件.首先,介绍了基于模式运动的控制系统动力学描述方法.针对描述方法中的强非线性的分类、度量映射难以采用可运算函数描述的问题,推导并建立了相应的控制系统非线性状态空间模型.然后,利用李雅普诺夫稳定性理论研究了在状态反馈控制下时间离散、状态离散的非线性系统渐近稳定的充分条件,建立了系统输出的类别划分、状态空间模型的线性部分系统矩阵与系统渐近稳定的关系.最后,采用烧结机实际生产数据与非线性数值算例对该方法进行了仿真实验,结果验证了所提条件的有效性.     

基于蔡氏电路的混沌同步的研究

该文采用研究混沌连续时间系统的同步方法，基于系统的稳定性准则，分析了蔡氏电路的混沌同步问题，即用同步误差的线性系统的稳定性分析来保证混沌的同步。通过系统的线性项和非线性项的适当分离，使系统的雅可比矩阵的全部特征值为负值，此时响应系统与驱动系统的状态变量之间，存在一个与初值有关的误差，无论初始同步误差多大。都能使同步误差e（t）最终趋于稳定，从而实现新、旧系统的完全同步。运用该方法对蔡氏电路进行计算机仿真实验，得到的仿真结果和分析相符，证明了该方法在研究非线性电路方面是简单有效的，为今后研究类似问题提出了新思路。     

不确定短时延网络控制系统的故障检测

针对远程被控对象为线性模型,且网络诱导时延小于一个采样周期的一类网络控制系统(NCS),假设可能发生执行器故障,对系统进行故障检测。将随机时延对系统的影响转化为未知有界条件下的不确定项,建立了系统的离散数学模型。按照时延补偿策略设计了系统的故障观测器,并基于Lyapunov稳定性定理和线性矩阵不等式理论,推导出了整个观测器系统全局渐近稳定的充分条件。仿真例子验证了方法的有效性。     

Using G.V. Shchipanov’s ideas to provide perturbation-invariance of the output of a distributed linear plant

Consideration was given to the possibility of using the ideas of G.V. Shchipanov in the design of the control system of a distributed linear plant exhibiting a close-to-invariant behavior is response to an external perturbation. The study was carried out both for an arbitrary inertialess plant and some variants of the one-dimensional heat-conducting plant. Cases where robustness of the “Shchipanov” system to imprecise observation of the absolute invariance condition was guaranteed and those where guaranteed was only stability of the closed-loop system were specified.     

小型无人直升机的姿态与高度自适应反步控制

针对小型无人直升机的姿态与高度控制问题, 本文提出了一种基于反步法的自适应控制策略. 具体而言, 首先对小型无人直升机的运动学模型进行了等效变换, 使系统中未知参数满足线性参数化条件, 然后应用反步法设计了包含主旋翼挥舞模型的姿态与高度自适应控制器, 并借助Lyapunov方法和芭芭拉定理对闭环系统的稳定性进行了严格的数学分析. 最后, 对该控制器的性能进行了仿真验证, 结果表明在直升机质量和惯性矩阵存在不确定性(未知)的情况下, 该控制算法依然能够取得良好的控制效果.     

Methods for stability evaluation for linear time varying,discrete-time systems on finite time horizon

This paper develops a method for determining stability of discrete-time (DT), linear time-varying (LTV) systems defined on a finite time horizon (FTH). In our considerations we use a collection of stability definitions for linear time invariant (LTI) and LTV systems which are defined on an infinite time horizon (ITH). Based on the analysis carried out and the introduced operator-matrix notation we define four stability functions. These functions allow examination of the stability of a system described by an LTV state space model. Moreover, using these functions we introduce the time stability margin and making use of the operator-matrix notation we propose a method of determining the stability on a finite time horizon. The theoretical considerations are numerically verified on two examples of LTV systems with a variable degree of non-stationarity depending on a parameter ε. Several examples illustrate the application of the introduced concepts and definitions to examination of the system stability also depending on parameter ε.     

Synchronization of unknown chaotic neural networks with stochastic perturbation and time delay in the leakage term based on adaptive control and parameter identification

In this paper, we investigate the synchronization problem of chaotic neural networks with unknown parameters, stochastic perturbation and time delay in the leakage term. A simple and robust adaptive controller is designed such that the response system can be synchronized with a drive system with unknown parameters by utilizing Lyapunov stability theory and parameter identification. Our synchronization criteria are easily verified and do not need to solve any linear matrix inequality. This research also demonstrates the effectiveness of application in secure communication. Numerical simulations are carried out to illustrate the main results.     

一种采用观测器的机器人变结构控制算法

本文针对仅有关节位置检测的关节型机器人,提出了一种考虑参数不确定性和状态不确 定性的变结构轨线跟踪控制算法.通过对两种不同类型观测器(线性反馈和变结构反馈)的研 究,用定理形式给出了由机器人、观测器和控制器组成的闭环系统渐近稳定的充分条件.非线 性滑动域替代线性滑动面取得了控制精度和控制平稳性的折衷.在作者自行研制的直接驱动 机器人DDR-1的实验中证实了这种算法的有效性.     

LESO-based Position Synchronization Control for Networked Multi-Axis Servo Systems With Time-Varying Delay

The position synchronization control (PSC) problem is studied for networked multi-axis servo systems (NMASSs) with time-varying delay that is smaller than one sampling period. To improve the control performance of the system, time-varying delays, modeling uncertainties, and external disturbances are first modeled as a lumped disturbance. Then, a linear extended state observer (LESO) is devised to estimate the system state and the lumped disturbance, and a linear feedback controller with disturbance compensation is designed to perform individual-axis tracking control. After that, a cross-coupled control approach is used to further improve synchronization performance. The bounded-input-bounded-output (BIBO) stability of the closed-loop control system is analyzed. Finally, both simulation and experiment are carried out to demonstrate the effectiveness of the proposed method.      

环形直流微电网的二次控制与稳定性分析

本文阐述了一种环形直流微电网系统分布式二次控制的稳定性分析方法,实现了微网系统的电压调控和电流分配.首先,借助多智能体系统的一致性算法,设计了局部观测器来估计所有分布式能源节点的平均电压.然后,基于观测器状态和邻居节点的电流信息设计了融合误差和动态反馈控制器,并通过解耦潮流代数方程得到了关于融合误差的闭环系统.进一步基...     

基于二维混合模型的重复控制系统设计新方法

现有重复控制方法是在一维空间上同时处理控制与学习过程, 这不利于重复控制系统的分析与设计. 本文针对一类线性不确定系统, 提出一种基于连续/离散二维混合模型的重复控制系统设计方法. 首先, 通过分析重复控制系统中独立存在的控制行为与学习行为, 建立重复控制系统的连续/离散二维混合模型, 将重复控制器设计问题转化为一类连续/离散二维系统的状态反馈控制问题; 然后应用二维连续/离散系统方法, 获得重复控制系统的稳定性条件, 根据稳定性条件并利用线性矩阵不等式(Linear matrix inequality, LMI)方法, 求得重复控制器参数. 与现有方法相比, 所提出的重复控制设计方法更加符合其本质特征, 具有简单实用、直观明了的特点, 克服了现有重复控制方法所存在的局限性. 最后, 数值仿真实例验证了本文所提方法的有效性.