On an output‐feedback stabilization problem with uncertainty in the relative degree

This paper deals with an output‐feedback finite‐time control problem for a class of nonlinear uncertain systems whose relative degree is affected by an uncertain system parameter and is therefore unknown at the stage of control design. We show that an existing second‐order sliding mode control algorithm can address successfully the control task of a finite‐time output‐feedback stabilization when the uncertain relative degree is equal to 1 or 2. We derive constructive tuning rules for the control parameters and show its effectiveness by using computer simulations. Copyright © 2007 John Wiley & Sons, Ltd.     

不确定线性系统鲁棒二次最优控制的时频域方法

利用时域和频域结合的方法,讨论了线性不确定系统鲁棒二次最优控制问题;提出了线性不确定系统鲁棒二次最优的概念,并证明了有关性质,建立了鲁棒回差方程,阐述了鲁棒二次最优控制系统的分析和综合方法;最后给出了工程应用设计实例。     

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.     

不确定非线性系统控制方法概述

不确定非线性系统的控制是目前国内外自动控制领域研究的一个热点。主要总结了近年来不确定非线性系统的控制方法，并分析了各种方法的优缺点。最后探讨了这一研究领域的研究趋向。     

基于输出反馈的不确定NCS鲁棒容错控制

研究了一类具有网络诱导时延和参数不确定性网络化控制系统鲁棒容错控制问题.基于将时延的不确定性转换为系统状态方程系数矩阵不确定性的NCS模型,同时考虑系统参数不确定性对系统的影响,应用Lyapunov稳定性理论和LMI方法,采用输出反馈控制策略,推证出了保证闭环网络化控制系统在执行器或传感器发生故障时仍渐进稳定的充分条件,并以求解线性矩阵不等式组给出了容错控制器的设计方法,最后用仿真算例验证了此方法的可行性和有效性.     

Output tracking control of uncertain nonlinear second-order systems

The solution of a tracking problem for a secondorder nonlinear system with uncertain dynamics and incomplete state measurement is obtained by means of a procedure directly inspired by the solution of the classical minimum-time optimal control problem. Two different types of uncertainty are considered in the paper: in the first case a constant bound on the uncertain dynamics is assumed to be known; in the second case, the bound is a function of both the measurable and the unmeasurable state variable of the system. In both cases, the possibility of applying the proposed control algorithms is proved to be determined by a proper choice of the control signal features. The resulting system is characterized by a suitable feedback switching logic and the convergence of the system trajectory to the desired one (or to a δ-vicinity of this latter) is proved also in the uncertain case.     

Adaptive fixed-time control for cluster synchronisation of coupled complex networks with uncertain disturbances

This paper focuses on the cluster synchronisation problem of coupled complex networks with uncertain disturbances under an adaptive fixed-time control strategy. To begin with, complex dynamical networks with community structure which are subject to uncertain disturbances are taken into account. Then, a novel adaptive control strategy combined with fixed-time techniques is proposed to guarantee the nodes in the communities to desired states in a settling time. In addition, the stability of complex error systems is theoretically proved based on Lyapunov stability theorem. At last, two examples are presented to verify the effectiveness of the proposed adaptive fixed-time control.     

一种离散型非线性自适应反馈控制器的设计与实现

针对运动控制低速跟踪系统中存在的非线性摩擦力影响的实际问题, 采用结构和参数完全未知的离散时间不确定非线性系统的反馈控制策略, 具体地进行了控制器的设计, 并利用MATLAB环境下的SIMULINK仿真来检验其控制效果, 进而运用到实际的电机控制系统中, 分析其控制性能, 并将其控制效果与PID控制相比较, 最后得出结论.     

Coherent H∞Control for Linear Quantum Systems With Uncertainties in the Interaction Hamiltonian

This work conducts robust H^∞analysis for a class of quantum systems subject to perturbations in the interaction Hamiltonian.A necessary and sufficient condition for the robustly strict bounded real property of this type of uncertain quantum system is proposed.This paper focuses on the study of coherent robust H^∞controller design for quantum systems with uncertainties in the interaction Hamiltonian.The desired controller is connected with the uncertain quantum system through direct and indirect couplings.A necessary and sufficient condition is provided to build a connection between the robust H^∞control problem and the scaled H^∞control problem.A numerical procedure is provided to obtain coefficients of a coherent controller.An example is presented to illustrate the controller design method.     

不确定参数下离散混沌系统的开闭环控制

在很多实际环境中,系统模型参数经常是不确定的,使离散混沌系统的控制策略可能不再有效。当参数不能直接观测时,开闭环控制方案将由于不精确的系统模型而失效。针对这个问题,提出了参数自适应开闲环控制策略来控制不确定参数的离散混沌系统。对开闲环控制在不确定参数条件下,参数变化满足控制需要的条件进行了讨论。同时,提出了参数自适应开闲环控制,将原有的开闭环控制推广到更大的范围。从Henon系统的仿真中,参数自适应开闲环控制策略显示了良好的抗扰动特性。     

控制增益符号未知的不确定非线性系统鲁棒自适应控制

针对一类控制增益函数及符号均未知的不确定非线性系统,基于反推滑模设计方法,提出一种鲁棒自适应神经网络控制方案.结合Nussbaum增益设计技术和神经网络逼近能力,取消了控制增益函数及符号已知的条件,应用积分型Lyapunov函数避免了控制器奇异性问题,并通过引入神经网络逼近误差和不确定干扰上界的自适应补偿项消除了建模误差和不确定干扰的影响.理论分析证明了闭环系统所有信号半全局一致终结有界,仿真结果验证了该方法的有效性.     

基于NCS时延模型的鲁棒容错控制器

研究了一类具有未知扰动和参数不确定性的网络化控制系统的鲁棒容错控制问题.针对NCS的时延和不同步对系统产生的影响,基于将时延的不确定性转换为系统状态方程系数矩阵不确定性的NCS模型,同时考虑系统参数不确定性和未知扰动对系统的影响,应用Lyapunov稳定性理论和LMI方法,采用状态反馈控制策略,推证出了保证闭环网络化控制系统在执行器或传感器发生失效故障时仍渐近稳定的充分条件,并通过求解线性矩阵不等式组方便地得到了容错控制器的设计方法,最后用仿真算例验证了此方法的可行性和有效性.     

具有时变不确定线性系统的鲁棒无源控制

研究具有时变不确定参数的线性系统在有界能量外部输入作用下的鲁棒无源控制问题. 目的是设计一个反馈控制器使得闭环系统是二次稳定,同时具有严格无源性.研究结果证明,这 一问题可以转化为一个等价的具有某个参数的线性时不变系统的正实控制问题,从而可用现有的 正实控制问题的求解方法解决所研究的问题.     

Adaptive‐impulsive consensus of multiagent systems

This paper studies the leader‐following consensus problem of multiagent nonlinear systems with uncertain parameters and control gain error. On the basis of the theory of impulsive differential equations, the adaptive control technique, and the Lyapunov stability theory, some novel adaptive‐impulsive consensus conditions are given to realize the consensus of a class of multiagent nonlinear systems. Compared with the existing investigations on the impulsive consensus of multiagent systems, the proposed impulsive control protocol with uncertain parameters and control gain error is more rigorous and effective in practical systems. Four numerical simulations are verified to confirm the effectiveness of the proposed methods.     

不确定系统控制的自稳定域方法的推广

基于已有的为构造不确定系统的连续反馈控制律而提出的自稳定域的理论,给出了推广的系统的自稳定域的概念及其构造方式的理论证明,使得零点成为系统自稳定域的内点,从而系统自稳定域不再仅限于第2、第4象限,保证了由此得到的系统在零点的连续性.基于这些理论结果,进一步给出了一般的2阶不确定系统控制的自稳定域以及相应的连续控制项的构造方法.并在文章最后给出了仿真计算的实例.     

The piecewise parametric optimal control of uncertain linear quadratic models

The optimal control of linear quadratic model is given in a feedback form and determined by the solution of a Riccati equation. However, the control-related Riccati equation usually cannot be solved analytically such that the form of optimal control will become more complex. In this paper, we consider a piecewise parametric optimal control problem of uncertain linear quadratic model for simplifying the form of optimal control. By introducing a piecewise control parameter, a piecewise parametric optimal control model is established. Then we present a parametric optimisation method for solving the optimal piecewise control parameter. Finally, an uncertain inventory-promotion optimal control problem is discussed and a comparison is made to show the effectiveness of proposed piecewise parametric optimal control model.     

Event-triggered synchronization control for complex networks with uncertain inner coupling

This paper is concerned with the event-triggered synchronization control problem for a class of complex networks with uncertain inner couplings. The uncertain inner coupling under consideration is characterized in terms of the interval matrix. In order to save the communication and computation resources, the event-based mechanism is adopted and the event-triggered synchronization control scheme is proposed for the complex networks. First, we transform the event-triggered synchronization control problem into the exponential stabilization problem for a new class of dynamical systems with multiple delays. Then, by employing the Lyapunov stability theory, we derive a sufficient condition under which the multi-delayed system is exponentially stable. Subsequently, a set of event-triggered synchronization controllers is designed in terms of the solution to a linear matrix inequality that can be solved effectively by using available software. Finally, a numerical simulation example is presented to show the effectiveness of the proposed event-triggered control scheme.     

不确定线性控制系统的实用稳定性

本文利用Ｌｙａｐｕｎｏｖ函数和Ｒｉｃｃａｔｉ矩阵方程研究不确定线性控制系统的实用稳定性，文中首先建立了一个比较原理，然后对不确定性线控制系统的实用稳定性得到了一个判据，文中定义了一类更广泛的容许集，文中给出了一个例子以说明本文主要的应用方法。     

广义不确定系统稳定鲁棒控制

利用李雅普诺夫稳定理论和矩阵范数性质研究了广义不确定系统的稳定鲁棒控制问题.在不同情况下,分别给出了保证闭环不确定系统渐进稳定的两类稳定鲁棒控制:状态反馈、正常动态补偿器的设计方法,得到了鲁棒稳定控制的不确定量的范数界,而且提出了在多个稳定鲁棒控制器中寻找具有最大的不确定量范数界的控制器的方案.     

Guaranteed-cost active disturbance rejection control for uncertain systems with an integral controller

Guaranteed-cost active disturbance rejection control (ADRC) for uncertain systems is investigated in this study. Firstly, an integral action is introduced in the framework of ADRC to measure and reduce the tracking error. Then, a robust stability condition is presented, and a quadratic cost function where the tracking error is appearing explicitly is used for ADRC performance assessment. The cost bound is formulated by linear matrix inequality and optimised to obtain controller parameters. Full-dimension extended state observer is used, and thus, the proposed strategy is applicable to an uncertain system that allows relative-degree varying or right-half-plane zero. Finally, the validity of the proposed method and its advantages is demonstrated through the simulations of comparative examples and experiments on a motor speed control system.