DoS攻击下的信息物理系统事件触发预测控制设计

针对信息物理系统(CPS)安全控制设计问题,提出拒绝服务(DoS)攻击下具有任意有界丢包的事件触发预测控制(ETPC)方法.首先,考虑DoS攻击能量的有限性及攻击行为的任意性,将DoS攻击描述为事件触发通信机制下的任意有界丢包;其次,在控制器端利用最近一次收到的状态信息进行控制器增益序列的预测设计以补偿DoS攻击造成的数据包丢失;随后,基于Lyapunov稳定性理论及切换系统分析方法考虑了DoS攻击下CPS的安全性并给出了控制序列设计方法.所提出的ETPC设计方法只需利用最近时刻收到的状态信息,无需满足传统CPS稳定性对最大允许丢包数的约束,为大时滞CPS的稳定性分析及控制提供了有效的解决方案.最后,通过仿真实例验证所提出的基于事件触发预测控制设计方法的有效性.     

DoS攻击下基于切换Luenberger观测器的冗余控制

研究了DoS攻击下网络化控制系统基于观测器的控制器设计问题.首先,提出了一种具有多个增益的切换Luenberger观测器,实现了无DoS攻击时系统状态的间歇性估计.根据获得的估计值,控制器同时计算了系统当前以及未来一段时域的控制信号,并将其封装在一个数据包中发送给执行器,保证了系统在有无DoS攻击时都有合适的控制输入更新.其次,利用构造的切换系统对DoS攻击下观测器与控制器的不同动态进行了统一的建模,基于多Lyapunov函数方法推导了任意切换律下系统指数稳定的充分条件,并给出了相应的观测器与控制器设计方法.最后,通过网络化倒立摆系统的实验验证了所提方法的有效性.     

DoS攻击下随机系统的攻击参数依赖型观测器与控制器协同设计EI北大核心CSCD

本文研究了拒绝服务攻击下网络随机控制系统的攻击参数依赖型观测器与控制器协同设计问题.首先,将拒绝服务(DoS)攻击建模为周期脉宽调制干扰信号,并构造了Luenberger观测器来估计不可测的系统状态.其次,设计了基于观测器的控制器,提出一种新的切换随机系统模型.然后,引入DoS攻击参数依赖型随机时变李雅普诺夫函数分析切换随机系统.给出了切换随机系统均方指数稳定的判据,并使闭环系统具有L_(2)增益性能水平.同时通过应用矩阵不等式技术,给出了攻击参数依赖型观测器与控制器的协同设计方案.最后,以一种飞行器系统为例,验证了该方案的有效性.     

欺骗攻击环境下具有执行器故障的跳变耦合 信息物理系统的同步控制

针对一类离散Markov跳变耦合信息物理系统(CPS)的同步控制问题,在考虑系统参数跳变、耦合参数跳变、控制信息不完全和人为攻击的情况下,设计同步控制器实现CPS的同步.首先,给出具有随机欺骗攻击和执行器故障的Markov跳变耦合CPS模型.其次,基于矩阵Kronecker积,得到同步误差系统,将CPS的同步控制问题转化为同步误差系统的稳定性分析问题.再次,通过构造合适的Lyapunov-Krasovskii泛函,并利用Lyapunov稳定性理论和线性矩阵不等式方法得到使同步误差系统稳定的充分条件,在此基础上,设计同步控制器实现对Markov跳变耦合CPS的同步控制.最后,通过数值仿真例子说明该同步控制器设计方法的有效性.     

拒绝服务攻击下的多输入多输出非线性系统无模型自适应控制

针对多输入多输出(MIMO)非线性离散时间系统,研究系统遭受拒绝服务(DoS)攻击和随机发生数据包丢失下的控制问题.首先采用两个独立的伯努利分布对周期性DoS攻击和随机发生的数据包丢失进行建模.其次结合DoS攻击设计无模型自适应控制(MFAC)算法,进而通过理论分析和数学推导证明所提算法的收敛性.并且通过结合先前时刻数...     

DoS攻击下网络控制系统的记忆型事件触发控制

针对一类网络化控制系统，当考虑网络控制系统遭受PWM （Pulsewidth-Modulated）型DoS （Denial-of-Service， DoS）攻击时，提出一种基于缓存机制的记忆型事件触发机制策略.本文考虑的DoS攻击可检测，并且攻击的周期时长以及每周期内的最短休眠时间已知.为了减少网络控制系统中数据包的发送频次，本文设计了基于相对误差的新型事件触发策略，与传统事件触发策略相比，通过增加缓存器来有效利用已经发送的历史采样数据，最终达到改善系统动态过程的目的.接下来，综合考虑网络攻击和事件触发方案，建立了网络化切换系统模型，构造分段李雅普诺夫泛函，推导出系统指数稳定的结论并且对控制器增益及事件触发参数进行协同设计.最后，通过仿真案例，验证了所提出方法的有效性.     

WSN中一种防御广播认证中的DoS攻击策略

当将数字签名应用到广播认证时,网络很容易受到DoS( Denial of Service)攻击,比如攻击者不停地广播虚假数据包从而消耗网络的通信资源和计算资源.针对这种情况,提出一种基于弱认证和信誉等级的协议来防御此类DoS攻击.该协议针对分簇的无线传感器网络模型,利用中国剩余定理和单向函数来完成弱认证,同时还引入信誉...     

工业无线传感器网络中干扰攻击的入侵检测

针对工业无线传感器网络的干扰攻击问题,采用一种基于统计过程控制理论控制图的入侵检测方法.选择数据包投递失败率作为度量属性,计算出对应的控制图上下限,通过监视传感器节点的数据包投递失败率是否在控制图的上下限内,判断节点是否处于被干扰攻击状态;基于工业无线传感器网络标准WirelessHART中采用的时隙跳频技术,建立一种干扰攻击模型,验证入侵检测方法的有效性.仿真结果表明干扰攻击检测方法能有效的检测出节点是否处于被干扰攻击状态,并且漏检率较低,随环境恶化时漏检率变化幅度较小.     

具有随机时延的网络控制系统周期反馈控制

针对一类具有随机时延的网络控制系统(NCSs)周期反馈控制问题,提出一个新颖的马尔可夫随机时滞系统模型.该模型包括一个分段常数广义采样保持函数(PCGSHF)以及一个用于描述网络诱导时延和数据包丢失的马尔可夫链.应用李亚普诺夫方法以及线性矩阵不等式技术得到了闭环 NCSs 随机稳定的充分条件,并给出了状态反馈控制器和 PCGSHF 的设计方法.最后,通过仿真算例验证了设计方法的有效性.     

DoS攻击下的幂次趋近律滑模控制系统稳定性分析

研究拒绝服务(denial-of-service, DoS)攻击下的n阶受扰系统基于幂次趋近律的滑模控制.首先,通过构造状态预测器重建攻击活跃期间丢失的系统状态,基于预测器状态和非光滑函数,设计能量受限型DoS攻击情况下的幂次趋近律滑模控制器,进一步分析保持系统稳定性的充分条件;其次,当系统存在外部干扰情况下,证明幂次趋近律滑模控制方法仍能保持非光滑控制器的强抗干扰能力;最后,通过数值仿真对所提出的理论证明结果进行验证.     

Guaranteed cost control of cyber‐physical systems with packet dropouts under dos jamming attacks

Cyber‐Physical Systems (CPSs) are vulnerable to malicious network attacks due to tight combination of cyber‐system and physical system through a more open network communication. In this paper, a guaranteed cost control problem for a CPS under DoS jamming attacks is solved via both state feedback and output feedback methods. Specifically, an energy constraint DoS jammer with clear periodic attack strategy is proposed to attack wireless channel and to degrade the system performance. Without knowing the DoS jammer's attack strategy, a passive attack‐tolerant mechanism is established, and the corresponding state feedback and output feedback controllers are designed to achieve guaranteed cost control for the CPS with inherent packet dropouts under DoS jamming attacks. Finally, numerical examples are presented to demonstrate the effectiveness of the guaranteed cost controllers.     

Observer-based H-infinity control in multiple channel networked control systems with random packet dropouts

This paper investigates the observer-based $H_{\infty}$ control problem for networked control systems (NCSs) with random packet dropouts. A general packet dropout model with multiple independent stochastic variables in multiple channels case is adopted to describe the data missing in the limited communication channels. With the consideration of the sensor-to-controller and controller-to-actuator packet dropouts at the same time, a new method is proposed based on a separation lemma to design an observer-based $H_{\infty}$ controller, which exponentially stabilizes the closed-loop system in the sense of mean square and also achieves a prescribed $H_{\infty}$ disturbance attenuation level. A numerical example is given to illustrate the effectiveness of the proposed control method.     

Resilient control for wireless networked control systems under DoS attack via a hierarchical game

In this paper, the resilient control problem is investigated for a wireless networked control system (WNCS) under denial‐of‐service (DoS) attack via a hierarchical game approach. In the presence of a wireless network, a DoS attacker leads to extra packet dropout in the cyber layer of WNCS by launching interference power. A zero‐sum Markov game is exploited to model the interaction between the transmitter and the DoS attacker under dynamic network environment. Additionally, with the attack‐induced packet loss, an H_∞ minimax controller is designed in the physical layer by using a delta operator approach. Both value iteration and Q‐learning methods are used to solve the hierarchical game problem for the WNCS. The proposed method is applied to a load frequency control system to illustrate the effectiveness.     

Network‐based H∞ control for stochastic systems

This paper investigates the problem of network‐based control for stochastic plants. A new model of stochastic time‐delay systems is presented where both network‐induced delays and packet dropouts are taken into consideration for a sampled‐data network‐based control system. This model consists of two successive delay components in the state, and we solve the network‐based H_∞ control problem based on this model by a new stochastic delay system approach. The controller design for the sampled‐data systems is carried out in terms of linear matrix inequalities. Finally, we illustrate the methodology by applying these results to an air vehicle control problem. Copyright © 2008 John Wiley & Sons, Ltd.     

Sampled‐data H∞ control for networked systems with random packet dropouts

This paper is concerned with the H_∞ control problem for networked control systems (NCSs) with random packet dropouts. The NCS is modeled as a sampled‐data system which involves a continuous plant, a digital controller, an event‐driven holder and network channels. In this model, two types of packet dropouts in the sensor‐to‐controller (S/C) side and controller‐to‐actuator (C/A) side are both considered, and are described by two mutually independent stochastic variables satisfying the Bernoulli binary distribution. By applying an input/output delay approach, the sampled‐data NCS is transformed into a continuous time‐delay system with stochastic parameters. An observer‐based control scheme is designed such that the closed‐loop NCS is stochastically exponentially mean‐square stable and the prescribed H_∞ disturbance attenuation level is also achieved. The controller design problem is transformed into a feasibility problem for a set of linear matrix inequalities (LMIs). A numerical example is given to illustrate the effectiveness of the proposed design method. Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society     

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．     

On designing network‐based H ∞ controllers for stochastic systems

This paper is concerned with network‐based H _∞ stabilization for stochastic systems, where network‐induced delays, packet dropouts, and packet disorders are taken into account simultaneously. The packet disorders arising from both the sampler‐to‐controller channel and the controller‐to‐actuator channel are considered by introducing a logic controller and a logic zero‐order hold. The network‐induced delays and packet dropouts are modeled as a constant delay plus a non‐differentiable time‐varying delay in the input. By employing Lyapunov–Krasovskii functional approach, we establish results that parallel well‐known bounded real Lemmas. More specifically, these results provide conditions to bound the H _∞ level of the system, which means the worst case energy of the output of the system when subjected to a unitary norm deterministic disturbance signal. On the basis of these results, suitable network‐based H _∞ controllers are designed by using cone complementary linearization method. An air vehicle system is finally taken as an example to show the effectiveness of the proposed method. Copyright © 2013 John Wiley & Sons, Ltd.     

H ∞ control for networked systems with random delays and packet dropouts

This paper is concerned with the control problem for a class of systems with random delays and packet dropouts which unavoidably occur during the data transmission in the network. A novel model is developed to describe the random one-step delays and multiple packet dropouts from sensors to controllers and from controllers to actuators by applying four Bernoulli distributed stochastic variables. An observer-based feedback controller is designed via a linear matrix inequality (LMI) approach which guarantees the closed-loop networked system to be exponentially stable in the sense of mean square and also achieves the prescribed H _?? disturbance-rejection-attenuation level. A simulation example shows the effectiveness of the proposed algorithm.