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.     

基于信号量化处理的随机时滞网络化系统的分析与设计

研究一类时滞分布依赖的网络化系统的量化控制问题.首先,在考虑信号量化处理的影响下,建立包含时延区间概率分布信息和信号量化信息的新的网络化系统模型;然后,运用Lyapunov稳定性理论、矩阵函数的凸性、自由权技术和Jessen不等式等分析方法给出系统渐近稳定和镇定的条件;最后,运用线性矩阵不等式（LMI）技术求解量化控制器.仿真结果和横向比较结果验证了所述方法的有效性.     

基于网络控制系统平均时延的模糊控制器设计

针对网络控制系统(NCS)中的随机时延问题,根据实际网络时延的分布情况,提出一种新的具有随机时廷的网络控制系统的建模方法--离散T-S模型,并在此基础上应用并行分布补偿原理(PDC)设计模糊控制器.同时提出一种新的模糊控制系统隶属函数的确定方法,利用Lyapunov定理和线性矩阵不等式(LMI)研究系统的稳定性问题,给出了基于LMI的模糊控制器的设计方法.最后通过仿真实例验证了该控制方法能使具有时延的网络控制系统稳定.     

具有数据包丢失及转移概率部分未知的网络控制系统H∞控制

研究一类具有数据包丢失及状态转移概率部分未知的网络控制系统随机稳定性及H∞控制问题．传感器与控制器之间、控制器与执行器之间存在数据包丢失的网络控制系统被建模成具有4个子系统的跳变系统,4个子系统之间的跳变遵行Markov跳变过程,并具有部分未知的跳变概率．利用Lyapunov稳定性定理及线性矩阵不等式的求解方法得到该类系统随机稳定的充分条件,并给出了相应的∞状态反馈控制器的设计方法．数值仿真结果验证了本文方法的正确性和有效性．     

Stochastic optimal control of unknown linear networked control system in the presence of random delays and packet losses

In this paper, the stochastic optimal control of linear networked control system (NCS) with uncertain system dynamics and in the presence of network imperfections such as random delays and packet losses is derived. The proposed stochastic optimal control method uses an adaptive estimator (AE) and ideas from Q-learning to solve the infinite horizon optimal regulation of unknown NCS with time-varying system matrices. Next, a stochastic suboptimal control scheme which uses AE and Q-learning is introduced for the regulation of unknown linear time-invariant NCS that is derived using certainty equivalence property. Update laws for online tuning the unknown parameters of the AE to obtain the Q-function are derived. Lyapunov theory is used to show that all signals are asymptotically stable (AS) and that the estimated control signals converge to optimal or suboptimal control inputs. Simulation results are included to show the effectiveness of the proposed schemes. The result is an optimal control scheme that operates forward-in-time manner for unknown linear systems in contrast with standard Riccati equation-based schemes which function backward-in-time.     

一类具有状态反馈NCS的H∞优化控制

研究一类网络控制系统(NCS)的H∞优化控制问题.状态反馈是兼顾系统性能和敏感性的最有效的控制方式,因此,针对一类不确定时延和有限能量干扰输入的状态反馈NCS,将其建模为不确定的线性时滞系统,并利用Lyapunov理论和线性矩阵不等式(LMI)研究H∞优化控制问题.首先给出NCS的鲁棒稳定的充分条件;然后给出NCS状态反馈次优和最优H;∞控制律的设计方法.仿真结果表明了该方法的可行性和有效性.

Abstract：

The H∞ optimal control problems of a class of networked control systems(NCS) is studied. The statefeedback is the most effective control mode, which combines system function and sensibility. Therefore, a class of state-feedback NCS with uncertain time-delay and limited energy disturbance input is modeled as the uncertain linear time-delay system. Then by using the Lyapunov theory and LMI, the problems about the H∞ optimal control are researched. The sufficient condition is first given for the robust stability of networked control system, and then the design methods of NCS state-feedback suboptimum and optimum H∞ control laws are obtained consequently. The simulation results show the feasibility and effectiveness of the results.     

存在通信约束和时延的多输入多输出网络控制系统镇定研究

讨论了一类存在通信约束和时延的多输入多输出网络控制系统（NCS）的建模和控制问题.该NCS具有多个传感器和执行器，由于网络通信受限,在同一时刻只能允许部分传感器和执行器访问网络.传感器和执行器访问网络的过程可以用两个马尔可夫链来描述,并且在假设传感器—控制器时延和控制器—执行器时延均为短时延的情况下,将整个闭环NCS建模成一个具有两个模式的马尔可夫切换系统.基于LMI技术和李亚普诺夫方法,给出了闭环NCS随机稳定的充分条件,并给出了状态反馈控制器的设计方法.最后的数值算例验证了所提方法的有效性.     

非线性时延网络控制系统的模糊建模与控制

针对时变网络诱导时延小于一个采样周期的非线性时延网络控制系统,讨论系统的稳定性及控制器的设计方法.利用基于“IF-THEN”规则的模糊模型近似系统中的非线性,将时延的不确定性转化为系统参数的不确定性,从而将此类非线性网络控制系统建模为一类具有参数不确定性的离散Takagi-Sugeno（T-S）模糊模型.基于建立的模型,利用Lyapunov方法和线性矩阵不等式方法,分析了系统的稳定性及模糊状态反馈控制器的设计方法,最后通过仿真实例验证了所提出方法的有效性.     

基于信噪比受限通道的网络控制系统镇定

研究了同时考虑通信和网络特性的线性系统镇定问题.首先针对连续时间网络控制系统,使用线性矩阵不等式方法得到了系统镇定所需要的最小信噪比;然后将问题推广到一类更为复杂的离散时间异构网络控制系统并得到了相似的结论.其中建立的多传感器随机时滞模型很好地刻画了token-passing总线控制网络,它更具有实际意义;最后通过数值例子对以上理论进行了仿真验证,有效表明了系统镇定时被控对象不稳定极点、网络时滞和信噪比之间的关系.     

具有数据包丢失的网络控制系统保性能控制

本文研究了一类具有数据包丢失的网络控制系统(NCSs)的建模和保性能控制问题.通过用两个马尔可夫链分别来描述前向通道和反馈通道的丢包过程,将闭环网络控制系统建模成具有两个模式的马尔可夫随机切换系统.基于线性矩阵不等式技术和李亚普诺夫方法得到了闭环系统随机稳定的充分条件,并给出了状态反馈保性能控制器的设计方法.最后通过数值算例验证本文结果的有效性.     

基于T-S模型的网络控制系统故障诊断

针对一类参数不确定并具有时延和丢包情况的非线性网络控制系统,为达到快速准确的进行故障诊断的目的,提出了一种基于T-S模糊模型的故障诊断方法.通过建立此系统的T-S模糊模型,利用平行分布补偿时延的思想设计了满足系统稳定性条件的状态反馈控制器,以及通过引入随机切换系统表示数据有无丢失情况下的基于模糊观测器的鲁棒故障诊断方法,然后基于 Lyapunov函数和线性矩阵不等式方法给出了该闭环网络控制系统渐近稳定的充分条件,最后通过仿真例子验证了该方法能够使闭环控制系统渐进稳定以及能够准确的进行故障诊断,验证了所设计方法的有效性.     

Network-based simultaneous <Emphasis Type="Italic">H</Emphasis><Subscript>∞</Subscript> stabilization for chemical reaction systems with multiple packet dropouts

In this paper, we study a novel control problem for network-based chemical reaction systems by virtue of a simultaneous H _∞ stabilization methodology. In the presence of multiple packet dropouts, a finite collection of stochastic parameter subsystems are extended to describe the networked control system (NCS). A single remote network-based controller is designed to simultaneously stabilize the multiple stochastic parameter subsystems in the sense of mean square and capture the H _∞ control performance. Based on an orthogonal complement space technique, a novel matrix inequality framework is established, where the controller gain is parametrized by the introduction of a common free positive definite matrix, which is independent of the multiple Lyapunov matrices. Furthermore, an iterative linear matrix inequality (ILMI) algorithm is developed to deal with the proposed framework. Simulation results of a typical network-based chemical reaction system are provided to illustrate the effectiveness of the proposed scheme.     

等式约束的网络化控制系统的稳定性设计

研究了等式约束的网络化控制系统的稳定性问题．在假设网络时滞是随机变化的，并且假设网络化控制系统的被控对象为一个具有等式约束的时滞系统的情况下，将网络化控制系统模型化为一个混合系统．然后采用李亚普诺夫函数、线性矩阵不等式的方法推导出了该混合系统渐近稳定的一个充分条件．根据此充分条件，通过求解一个线性矩阵不等式，较容易地获得系统的最大允许网络时滞以及此时的控制器．最后给出一个具体的数值和仿真实例说明了此设计方法是有效的．     

Stabilization of nonlinear networked probabilistic interval delay systems with sensor random packet dropout

In this paper, the problem of stabilization for nonlinear networked systems with probabilistic interval delay and sensor random packet dropout is investigated. By employing the information of probabilistic distribution of time‐varying delay and considering random sensor packet dropout with compensation, the nonlinear stochastic delayed system model is established. Based on the obtained model, by choosing an appropriate Lyapunov function and utilizing a new discrete Jensen‐type inequality, sufficient conditions are derived to obtain the relation of the maximum allowable delay bound, delay interval occurrence rate and packet dropout rate to the stochastic stability of nonlinear networked control systems. Two kinds of design procedures for output feedback controller are also presented in terms of solving corresponding linear matrix inequalities. Numerical examples are provided to illustrate the effectiveness and applicability of proposed techniques. Copyright © 2011 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society     

Stochastic Optimal Design for Unknown Linear Discrete‐Time System Zero‐Sum Games in Input‐Output form Under Communication Constraints

In this paper, stochastic optimal strategy for unknown linear discrete‐time system quadratic zero‐sum games in input‐output form with communication imperfections such as network‐induced delays and packet losses, otherwise referred to as networked control system (NCS) zero‐sum games, relating to the H_∞ optimal control problem is solved in a forward‐in‐time manner. First, the linear discrete‐time zero sum state space representation is transformed into a linear NCS in the state space form after incorporating random delays and packet losses and then into the input‐output form. Subsequently, the stochastic optimal approach, referred to as adaptive dynamic programming (ADP), is introduced which estimates the cost or value function to solve the infinite horizon optimal regulation of unknown linear NCS quadratic zero‐sum games in the presence of communication imperfections. The optimal control and worst case disturbance inputs are derived based on the estimated value function in the absence of state measurements. An update law for tuning the unknown parameters of the value function estimator is derived and Lyapunov theory is used to show that all signals are asymptotically stable (AS) and that the estimated control and disturbance signals converge to optimal control and worst case disturbances, respectively. Simulation results are included to verify the theoretical claims.     

Stabilization for T-S model based uncertain stochastic systems

This paper considers the stabilization problem of a class of uncertain Itô stochastic fuzzy systems driven by a multidimensional Wiener process. The uncertainty modeled in the systems is of the linear fractional type which includes the norm-bounded uncertainty as a special case. The objective is to design a state-feedback fuzzy controller such that the closed-loop system is robustly asymptotically stable under a stochastic setting. By using a stochastic Lyapunov approach, sufficiency conditions for the stability and stabilization of this class of systems are established based on a novel matrix decomposition technique. The derived stability conditions are then employed to design controllers which stabilize the uncertain Itô stochastic fuzzy systems. Two simulation examples are given to illustrate the effectiveness of the approaches proposed.     

Sufficient conditions for stability and stabilization of networked control systems with uncertainties and nonlinearities

In this paper, we consider the problem of robust stability and stabilization for networked control systems (NCS) with uncertain/nonlinear dynamics AUTHOR: Please check that authors and their affiliations are correct. in which the network‐induced delays are time‐varying and bounded. Based on some recent achievements, a relatively simple Lyapunov–Krasovskii functional is proposed to derive sufficient conditions both for analysis and synthesis of NCS in the form of LMIs depending on the delay bounds. The effectiveness of the proposed method is illustrated by several benchmark examples available in the literature. Copyright © 2014 John Wiley & Sons, Ltd.     

Fault tolerant control for networked control systems with packet loss and time delay

In this paper, a fault tolerant control with the consideration of actuator fault for a networked control system (NCS) with packet loss is addressed. The NCS with data packet loss can be described as a switched system model. Packet loss dependent Lyapunov function is used and a fault tolerant controller is proposed respectively for arbitrary packet loss process and Markovian packet loss process. Considering a controlled plant with external energy-bounded disturbance, a robust H _∞ fault tolerant controller is designed for the NCS. These results are also expanded to the NCS with packet loss and networked-induced delay. Numerical examples are given to illustrate the effectiveness of the proposed design method.     

具有随机长时延的网络控制系统保性能控制

本文研究了一类具有随机长时延离散时间网络控制系统(NCSs)的建模和保性能控制问题.用两个马尔可夫链分别来描述反馈通道和前向通道的网络诱导时延,基于采用现有最新数据的原则,将闭环NCS建模成一个与当前时刻和过去时刻网络诱导时延有关的马尔可夫随机时滞系统.应用线性矩阵不等式技术和李亚普诺夫方法得到了闭环NCS随机稳定且具有二次性能指标上界的充分条件,并给出了状态反馈保性能控制器的设计方法.最后,通过数值算例验证了本文方法的有效性.     

具有控制约束的网络控制系统的鲁棒H_∞控制

针对具有控制约束的网络控制系统(Networked Control Systems,NCS)的特点,建立了具有外部扰动的网络控制系统模型,对其H∞性能加以分析和研究,并验证所取得的理论成果.假设具有控制约束的网络控制系统的H∞控制器与执行器均为事件驱动,传感器为时间驱动,且网络诱导时延小于传感器的采样周期,然后将此类网络控制系统的广义被控对象建模为一类线性离散系统,运用Lyapunov函数和线性矩阵不等式(LMI),导出闭环系统渐近稳定且满足给定H∞性能指标的充分条件,并给出了控制器的具体求法.得到了系统的H∞控制器存在条件及具体方法,通过设计该控制器,使具有外部扰动的网络控制系统的性能有很大的改善,通过Matlab仿真证明该控制器行之有效.