一类基于观测器的网络控制系统鲁棒控制器设计

研究一类基于状态观测器的网络控制系统鲁棒稳定性和鲁棒控制器设计问题.考虑传感器时钟驱动、控制器和执行器事件驱动以及小于等于一个采样周期的不确定时延,建立了基于状态观测器的网络控制系统增广模型.利用线性矩阵不等式方法推导出该系统鲁棒稳定的条件,进一步给出了鲁棒控制律和状态观测器设计方法.数值仿真算例证明了分析方法和结果的有效性.     

带有状态观测器的网络控制系统非脆弱H_∞控制

研究了存在时变时延的非理想网络环境下基于状态观测器的网络化控制系统非脆弱H_∞鲁棒控制。考虑状态观测器和控制器均存在不确定性,采用Lyapunov稳定性理论和线性矩阵不等式(Linear Matrix Inequality,LMI)方法,得到闭环控制系统H_∞渐近稳定的充分条件,给出非脆弱状态观测器和非脆弱鲁棒控制器的存在条件,通过给出的锥补线性化算法求解控制器和观测器增益矩阵。仿真实例表明了所提方法的有效性和可行性。     

Lurie网络化控制系统的保性能控制

以不确定Lurie系统作为被控对象,研究其在网络环境下的保性能控制问题.在同时考虑随机网络诱导时延和数据丢包的情况下,建立不确定Lurie网络化控制系统模型;利用Lyapunov方法分别给出了存在结构不确定性和范数有界的不确定性时,Lurie网络化控制系统保性能控制器的设计方法.所得结果是以线性矩阵不等式的形式给出的,便于数值求解.最后以数值实例说明了所提出方法的可行性和有效性.     

短时滞网络控制系统鲁棒稳定性分析

本文主要研究了网络控制系统时延小于一个采样周期的稳定性,以及系统在扰动下控制器设计的问题,利用线性矩阵不等式方法得出离散时滞网络控制系统Lyapunov稳定性判据,同时给出了具有不确定性系统的鲁棒控制器。     

Lurie网络化控制系统的保性能控制

以不确定Lurie系统作为被控对象,研究其在网络环境下的保性能控制问题.在同时考虑随机网络诱导时延和数据丢包的情况下,建立不确定Lurie网络化控制系统模型,利用Lyapuniv方法分别给出了存在结构不确定性和范数有界的不确定性时,Lurie网络化控制系统保性能控制器的设计方法.所得结果是以线性矩阵不等式的形式给出的,便于数值求解.最后以数值实例说明了所提出方法的可行性和有效性.

     

基于等分采样的网络控制系统鲁棒故障检测

考虑一类具有未知干扰的时延网络控制系统,对其进行故障检测。通过提高控制器端的采样频率,等分传感器采样周期,将网络时延近似看成控制器端采样周期的整数倍。建立基于离散切换系统的鲁棒H∞故障观测器,将观测器稳定条件归结为一个线性矩阵不等式。通过求解具有线性矩阵不等式约束的最小化问题,对故障检测阈值进行选取,从而增强检测的鲁棒性和灵敏度。仿真示例验证了该方法的有效性。     

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.     

基于T-S 模糊模型的一类非线性网络控制系统故障检测

针对同时存在网络时延和数据包丢失的网络环境,研究了一类非线性网络控制系统的鲁棒故障检测问 题．基于不确定T-S 模糊模型描述的非线性网络控制系统模型,完成了网络环境下鲁棒故障检测观测器的设计,使 得残差信号对故障敏感而对外部扰动具有鲁棒性．构造Lyapunov-Krasovskii 函数,并引入一个积分不等式,给出了 使得观测器误差动态系统渐近稳定的充分条件．采用线性矩阵不等式技术将鲁棒故障检测问题转化为具有线性矩阵 不等式约束的凸优化问题求解．仿真算例验证了上述方法应用于此类系统的故障检测的有效性．     

不确定变时滞系统的状态观测器与基于观测是器的鲁棒控制器设计

研究了具有变时滞的不确定系统的状态观测器和基于观测器的鲁棒控制器设计问 题,其中不确定性是时变的,不要求满足匹配条件.通过构造增广系统,利用线性矩阵不等式 (LMI)方法,获得了该不确定系统存在状态观测器和基于观测器的鲁捧控制器的充分条件, 同时给出了相应的状态观测器和基于观测器的鲁棒控制器.     

变采样网络控制系统的鲁棒控制

对于线性时不变控制对象,在控制器和控制对象都采用时间-事件驱动时系统就变成便采样网络控制系统,当网络时延不确定时,在小于或者等于一个变采样周期时,基于动态输出反馈对变采样网络控制系统进行建模,使用李雅普诺夫方法和线性矩阵不等式研究了系统的鲁棒稳定性,并设计了鲁棒控制器,最后给出实例证明在鲁棒控制器的控制下系统稳定。     

Absolute stability of Lurie networked control systems

This paper is concerned with the absolute stability problem of networked control systems (NCSs) with the controlled plant being Lurie systems (Lurie NCSs), in which the network‐induced delays are assumed to be time‐varying and bounded. First, in consideration of both the time‐varying network‐induced delays and data packet dropouts, the Lurie NCSs can be modeled as a multiple‐delays Lurie system. Then, a delay‐dependent absolute stability condition is established by using the Lyapunov–Krasovskii method. Next, two approaches to controller design are proposed in the terms of simple algebra criteria, which are easily solved via the toolbox in Matlab. Furthermore, the main results can be extended to robust absolute stability of Lurie NCSs with the structured uncertainties, where robust absolute stability conditions and approaches to robust controller design are presented. Finally, two numerical examples are worked out to illustrate the feasibility and the effectiveness of the proposed method. Copyright © 2009 John Wiley & Sons, Ltd.     

Non-fragile observer-based robust control for a class of fractional-order nonlinear systems

The paper is concerned with the problem of the observer-based robust control for a class of fractional-order nonlinear systems. First, by introducing a continuous frequency distributed equivalent model and using indirect Lyapunov approach, the sufficient condition for robust asymptotic stability of the closed-loop system via state observer-based control is presented, which is less conservative than some existing ones in recent literature. Next, using matrix’s singular value decomposition (SVD) and linear matrix inequality (LMI) techniques, the existence condition and method of designing a robust non-fragile observer-based controller are derived. Finally, the validity of the proposed methods are demonstrated by two numerical examples.     

Observer-based output feedback control of networked control systems with non-uniform sampling and time-varying delay

This paper investigates the problem of observer-based output feedback control for networked control systems with non-uniform sampling and time-varying transmission delay. The sampling intervals are assumed to vary within a given interval. The transmission delay belongs to a known interval. A discrete-time model is first established, which contains time-varying delay and norm-bounded uncertainties coming from non-uniform sampling intervals. It is then converted to an interconnection of two subsystems in which the forward channel is delay-free. The scaled small gain theorem is used to derive the stability condition for the closed-loop system. Moreover, the observer-based output feedback controller design method is proposed by utilising a modified cone complementary linearisation algorithm. Finally, numerical examples illustrate the validity and superiority of the proposed method.     

Dynamic observer-based controllers for linear uncertain systems

This paper addresses robust controller design for uncertain linear systems via a dynamic observer-based controller. A dynamic observer is an alternative structure for a classical observer which can be regarded as a general form of a usual observer and has additional degrees of freedom in the observer structure. Using this new observer structure, a new observer-based controller for linear systems is proposed. Some strict linear matrix inequalities (LMIs) have been given to find the dynamic observer parameters and controller gain. It is shown that dynamic observer can be used effectively for tackling the drawbacks of the classical observer-based robust controller design methods. As an advantage, LMIs are derived even in the presence of uncertainties in system, input and output matrices simultaneously, whereas by using the traditional observer, bilinear matrix inequalities (BMIs) are given in the presence of such uncertainties. Moreover, the proposed LMIs do not imply the equality constraint. Simulation results are used to illustrate the effectiveness of the proposed design technique.     

Non‐fragile robust control for networked control systems with long time‐varying delay,randomly occurring nonlinearity,and randomly occurring controller gain fluctuation

This paper investigates the non‐fragile robust control problem for a class of nonlinear networked control systems (NCSs) with long time‐varying delay. Both the uncertain nonlinearity and the controller gain fluctuation enter into the system in random ways, and such randomly occurring nonlinearity and randomly occurring controller gain fluctuation obey certain mutually uncorrelated Bernoulli distributed white noise sequences. A new time‐varying discrete time system model is proposed to describe the NCS. To reduce conservatism arising from modeling time‐varying parts, the time‐varying parts due to the time‐varying delay are treated as a norm‐bounded uncertainty with one nominal point using robust control techniques. Based on the obtained uncertain system model, a regular and an optimal sufficient non‐fragile controllers are derived by applying the Lyapunov stability theory and the linear matrix inequality technique, which render the closed‐loop NCS to be asymptotically stable and guarantee an upper bound of the given performance cost for all admissible uncertainties. Moreover, the existence condition and design method for the non‐fragile stabilizing controllers are also presented. Two numerical examples are provided to demonstrate the effectiveness of the proposed scheme. Copyright © 2015 John Wiley & Sons, Ltd.     

Absolute stability and stabilization for Lurie networked control systems

This paper investigates the problem of absolute stability and stabilization for networked control systems (NCSs) with the controlled plant being Lurie systems (Lurie NCSs), in which the network‐induced delays are assumed to be time‐varying and bounded. By considering the relationship between the network‐induced delay and its upper bound, an improved stability criterion for networked control system is proposed. Furthermore, the resulting condition is extended to design a state feedback controller by employing an improved cone complementary linearization (ICCL) algorithm. A numerical example is worked out to illustrate the effectiveness and the benefits of the proposed method. Copyright © 2010 John Wiley & Sons, Ltd.     

丢包网络化控制系统非脆弱量化H∞控制

针对非线性网络化控制（NCS）系统中控制器参数存在摄动的问题,考虑传感器—控制器和控制器—执行器均存在随机丢包和量化误差,提出了一种加性非脆弱量化H_∞控制器的设计方法．利用李亚普诺夫稳定性理论和线性矩阵不等式（LMI）方法,将该问题转化为线性矩阵不等式约束和线性目标函数的凸优化问题进行求解,给出了丢包下的非脆弱量化H_∞控制器存在的充分条件．所设计的控制器在容许的参数摄动、丢包概率和量化密度条件下,不仅能保证闭环NCS的稳定性和性能要求,而且是非脆弱的．数值仿真验证了所提方法的有效性．     

时延网络控制系统的模型预测控制

针对有输入约束的不确定时延网络控制系统,提出鲁棒模型预测控制方法;其中,将不确定时延建模为范数有界的输入矩阵的不确定性．给出了鲁棒性能指标的上界和系统渐近稳定的充分条件,通过在线求解LMI凸优化问题得到状态反馈控制律．仿真例子验证了该方法的有效性．     

Non-monotonic robust H2 fuzzy observer-based control for discrete time nonlinear systems with parametric uncertainties

A non-monotonic Lyapunov function (NMLF) is deployed to design a robust H₂ fuzzy observer-based control problem for discrete-time nonlinear systems in the presence of parametric uncertainties. The uncertain nonlinear system is presented as a Takagi and Sugeno (T–S) fuzzy model with norm-bounded uncertainties. The states of the fuzzy system are estimated by a fuzzy observer and the control design is established based on a parallel distributed compensation scheme. In order to derive a sufficient condition to establish the global asymptotic stability of the proposed closed-loop fuzzy system, an NMLF is adopted and an upper bound on the quadratic cost function is provided. The existence of a robust H₂ fuzzy observer-based controller is expressed as a sufficient condition in the form of linear matrix inequalities (LMIs) and a sub-optimal fuzzy observer-based controller in the sense of cost bound minimization is obtained by utilising the aforementioned LMI optimisation techniques. Finally, the effectiveness of the proposed scheme is shown through an example.