Fault detection for discrete-time networked nonlinear systems with incomplete measurements

This article addresses the problem of fault detection (FD) for discrete-time networked systems with global Lipschitz nonlinearities and incomplete measurements, including time delays, packet dropouts and signal quantisation. By utilising a discrete-time homogeneous Markov chain, an improved model which considers packet dropout compensation has been proposed to describe the above network-induced phenomena. We aim to design a mode-dependent fault detection filter (FDF) such that the FD system is asymptotically mean-square stable and satisfies a prescribed attenuation level. The addressed FD problem is then converted into an auxiliary H _∞ filtering problem of Markov jump system with time-varying delay. A sufficient condition for the existence of the FDF is derived in terms of certain linear matrix inequalities (LMIs). When these LMIs are feasible, the explicit expression of the desired FDF can also be characterised. A numerical example is exploited to show the effectiveness of the results obtained.     

具有随机丢包的网络化多自主体系统的一致性

研究具有随机丢包的网络化多自主体系统的均方一致性问题,其中不同自主体间的通信通道具有相同的丢包情况并且均服从马尔可夫(Markov)分布。首先,利用系统变换和迭代方法,得到了系统达到均方一致的一个初等充要条件。然后,利用矩阵理论和图论知识,如果拓扑图含有有向生成树,则可以将系统的均方一致性转化成一个线性Markov跳变系统的均方稳定性,并且可以建立线性矩阵不等式形式的均方可镇定准则。最后,通过相应的仿真实例说明了所得结论的可行性。     

网络控制系统随机稳定性研究

研究了具有随机网络诱导时延及数据包丢失的网络控制系统随机稳定性问题. 本文用一个具有两个状态的马尔可夫链来描述数据通过网络传输时随机数据包丢失过程, 利用马尔可夫跳变线性系统理论, 将网络控制系统建模为一个具有两种运行模式的马尔可夫跳变线性系统, 给出了在状态反馈控制下网络控制系统随机稳定的线性矩阵不等式形式的充分条件, 最后用一个仿真示例验证了该方法的有效性.     

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．     

不确定有损网络控制系统的鲁棒镇定

The data packet dropouts phenomenon is usually inevitable when information transmitted among communication networks. In this paper, the robust stabilization problem for uncertain networked control systems with data packet dropouts is studied. First, an uncertain discrete-time switching system model is presented to describe these networked control systems. The stability equivalence is then proved between this switching system and an uncertain impulsive difference system. Moreover, a sufficient condition is obtained for the asymptotical stability of the nonlinear impulsive difference system. From this condition the robust stabilization problem is dealt with for the uncertain impulsive system. Main results are given in linear matrix inequalities. Finally a numerical example is given to illustrate the theoretical results.     

一类丢包时延网络控制系统的鲁棒H∞滤波

用随机马尔可夫跳变系统描述一类具有丢包时延的网络控制系统．为这类网络控制系统设计马尔可夫跳变滤波器,保证了滤波误差系统均方意义下随机渐近稳定,且噪声信号对估计误差的影响低于指定H∞ 性能水平,滤波器参数可通过求解线性矩阵不等式得到．最后通过仿真实例验证了所得结论的正确性和滤波器设计方法的有效性．     

时延加权融合技术的无线传感器网络控制

本文研究了无线传感器网络控制系统的建模、稳定性与控制器设计问题.首先建立一个新的无线传感器网络控制系统模型,然后提出一种用于多个传感器数据融合的时延相关加权均值方法,并通过系统建模及分析,把无线传感器网络控制系统稳定性问题转换成为具有多个传输时延和丢包现象的多传感器单控制器网络控制系统稳定性问题.并利用线性跳变系统理论...     

具有双边随机时延和丢包的网络控制系统有限时间控制

针对双边丢包和双边时延的网络化控制系统的有限时间控制问题,通过引入时间偏移量的方法,将丢包转换为时延,从而形成多时延系统,并将时间延迟转换为系统状态延迟。基于全概率公式给出已知网络丢包率下连续丢包的概率公式,用Markov链表征网络时延的变化规律。以线性矩阵不等式的形式给出改进的有限时间时延相关稳定性判据,并通过数值仿真验证所提方法的有效性。     

一类随机时延网络化控制系统的容错控制研究

将一类具有随机时延的网络化控制系统建模为具有马尔可夫延迟特性的离散跳变线性系统．借助跳变线性系统理论和容错控制的思想，研究了随机时延网络化控制系统的执行器失效问题．仿真结果验证了所提方法的有效性．     

Compensation and stochastic modeling of discrete-time networked control systems with data packet disorder

Data packet disorder is inevitable in discrete-time networked control systems, which however has been ignored in most literature to date. This work investigates the cause and the negative effects of data packet disorder in discrete-time networked control systems, and a compensation scheme is proposed to deal with these negative effects. This analysis shows that most existing works in the related areas have assumed unrealistic characteristics of the communication network and thus further improvements within this new framework are necessary. For this purpose the closed-loop system with the use of the proposed compensation scheme is mathematically modeled as a Markov jump systems, and stochastic stability and stabilization results are then obtained. Numerical examples illustrate the negative effects caused by data packet disorder and also the effectiveness of the proposed approach.     

具有随机丢包的网络控制系统的镇定

研究具有随机丢包的网络控制系统(NCS)的镇定问题.同时考虑传感器节点到控制器节点(S/C)和控制器节点到执行器节点(C/A)的随机丢包,并分别对这两种丢包现象建模.基于Lyapunov稳定性理论,得到闭环系统全局均方渐近稳定的充分条件.进一步利用线性矩阵不等式(LMI)方法,得到状态反馈控制律的增益矩阵.数值仿真算例验证了所得结果的有效性.     

Robust Stabilization of Uncertain Networked Control Systems with Data Packet Dropouts

The data packet dropouts phenomenon is usually inevitable when information transmit- ted among communication networks.In this paper,the robust stabilization problem for uncertain networked control systems with data packet dropouts is studied.First,an uncertain discrete-time switching system model is presented to describe these networked control systems.The stability equiv- alence is then proved between this switching system and an uncertain impulsive difference system. Moreover,a sufficient condition is obtained for the asymptotical stability of the nonlinear impulsive difference system.From this condition the robust stabilization problem is dealt with for the uncertain impulsive system.Main results are given in linear matrix inequalities.Finally a numerical example is given to illustrate the theoretical results.     

离散线性切换系统的一致有限时间稳定分析和反馈控制及其在网络控制系统中的应用

研究了一类离散线性切换系统的一致有限时间稳定性分析和反馈镇定．基于线性矩阵不等式技术,给出了在任意切换信号作用下,离散线性切换系统有限时间稳定和有限时间有界的充分条件,并给出了离散线性切换控制系统一致有限时间状态反馈控制器的设计方法．将上述分析结果应用于一类丢包有界的网络控制系统,得到了保证其有限时间稳定的反馈控制器．最后,通过两个数值仿真例子验证了所提方法的有效性．     

具有Markovian时延与丢包的离散系统的状态估计

网络化控制系统中经常会因网络带宽有限而导致数据包在网络中传输时产生时延甚至丢失.本文主要研究具有Markovian时延与丢包的离散线性系统的状态估计问题.通过在估计器端设置适当长度的缓存器,把具有多状态Markovian时延与丢包的离散定常系统建模成数据包到达过程为两状态Markovian模型的离散时变系统,并基于跳跃线性估计器的思想提出了一类特殊的估计器,即限定接收历史估计器 (FRHE).在最大时延已知时,给出了可选增益的最优RHE设计策略.该策略虽然是次优,却能提供简便的计算.通过与时变Kalman估计器 (TVKE)的仿真对比,表明所提策略的有效性.     

具有随机丢包的关联系统的分散控制

研究了在子系统之间信息传输存在随机丢包现象时关联大系统的性能分析及控制器设计问题. 通过引入空间变量及空间移动算子, 将关联系统建模成具有Markovian跳变参数的关于离散时间变量和空间变量的多维系统, 结合跳变系统有界实引理, 得到使整个关联系统均方稳定并满足一定性能指标的解析条件. 然后基于线性矩阵不等式变换给出确保关联大系统鲁棒均方稳定性的一种分散输出反馈控制器的设计方法. 最后通过一组多机器人直线编队的例子说明本文算法的正确性和有效性.     

具有双边随机时延和丢包的网络控制系统稳定性分析

针对具有双边随机网络时延和丢包的网络控制系统,首先基于Markov的随机过程描述系统丢包的特性;然后利用系统增广矩阵的方法建立参数不确定的离散时间跳变系统模型,在考虑Markov链转移概率矩阵中部分元素未知甚至完全未知的条件下,采用Lyapunov稳定理论和随机理论的分析方法,设计依赖于丢包特性且满足系统均方稳定要求的时变控制器;最后通过数值算例仿真表明所提出方法的有效性.     

具有随机丢包的一类网络控制系统的故障检测

针对存在随机数据包丢失的网络环境,研究了一类网络控制系统的故障检测问题.考虑随机丢包同时发生在传感器与控制器以及控制器与执行器之间,将网络控制系统建模为含有4个模态的马尔可夫跳变线性系统.基于此类模型,构造了系统的残差发生器,相应的故障检测问题转化为H∞滤波问题.利用马尔可夫跳变线性系统理论,设计了故障检测滤波器,使得...     

具有双通道数据包丢失的Delta算子系统故障检测

研究同时存在双通道数据包丢失和时变时延的Delta算子网络控制系统（NCSs）故障检测问题.假定数据包丢失发生在控制器到执行器、传感器至控制器的数据传输过程中，并且利用两个相互独立的伯努利随机变量描述是否发生丢包.将上述的NCSs建模为网络切换系统，提出任意切换律下故障检测滤波器的设计方法.利用线性矩阵不等式（LMIs）方法、Lyapunov-Krasovskii泛函和平均驻留时间等得出所考虑的网络切换系统具备指数均方稳定性的充分条件.证明了所用的网络切换系统满足H_∞性能，并推导出了滤波器参数的显式表达.数值仿真结果验证了所提方法的有效性.     

Output feedback guaranteed cost control of networked linear systems with random packet losses

This article is concerned with the output feedback guaranteed cost control problem for a class of networked control systems (NCSs) with both packet losses and network-induced delays. The packet-loss processes in the forward channel and the backward channel are modelled as two Markov chains. The dynamic output feedback controllers are considered, and the closed-loop NCS is modelled as a discrete-time Markovian system with two modes and unit time delay. By using a properly constructed Lyapunov function and the state transformation technique, a sufficient condition is derived for the closed-loop NCS to be mean-square exponentially stable and ensure a decay rate that can be tuned according to the packet loss situations in the networks. Moreover, design procedures for the guaranteed cost controllers are also presented based on the obtained stability condition and guaranteed cost performance result. Finally, an illustrative example is given to demonstrate the effectiveness of the proposed results.     

Stability and stabilization of linear sampled-data systems with multi-rate samplers and time driven zero order holds

In multi-rate sampled-data systems, a continuous-time plant is controlled by a discrete-time controller which is located in the feedback loop between sensors with different sampling rates and actuators with different refresh rates. The main contribution of this paper is to propose sufficient Krasovskii-based stability and stabilization criteria for linear sampled-data systems, with multi-rate samplers and time driven zero order holds. For stability analysis, it is assumed that an exponentially stabilizing controller is already designed in continuous-time and is implemented as a discrete-time controller. For each sensor (or actuator), the problem of finding an upper bound on the lowest sampling frequency (or refresh rate) that guarantees exponential stability is cast as an optimization problem in terms of linear matrix inequalities (LMIs). Furthermore, sufficient conditions for controller synthesis are formulated as LMIs. It is shown through examples that choosing the right sensors (or actuators) with adequate sampling frequencies (or refresh rates) has a considerable impact on stability of the closed-loop system.