拒绝服务攻击下直流微电网的事件触发控制

本文研究受拒绝服务攻击下直流微电网的事件触发控制问题. 考虑到直流微电网的状态并不总是可获得, 设计了一个观测器来估计直流微电网的状态. 基于观测器的估计状态, 对于受拒绝服务攻击的直流微电网设计了一种新颖的弹性攻击的事件触发控制器. 所提出的控制器设计方法可以通过分离方法转化成一个凸问题. 此外, 在所设计的事件触发机制中, Zeno行为也被讨论并且通过矛盾法被排除. 最后, 一个实际的电网例子被用来验证所提出的控制方案的有效性.     

自适应事件触发通信机制下机理解析与数据驱动融合的ICPS双重安全控制

针对存在拒绝服务(DoS)攻击与执行器故障的工业信息物理融合系统(ICPS),将机理解析与数据驱动方法相结合,在新型自适应事件触发通信机制下,研究双重安全控制问题.首先,设计自适应事件触发机制,能够触发参数随系统行为动态自适应变化,节约更多网络通信资源;其次,基于系统最大允许时延建立攻击检测机制,可以有效区分大、小能量DoS攻击;再次,基于极限学习机算法(ELM)建立时序预测模型,用于大能量DoS攻击时重构修正控制量,以主动容侵攻击的影响,并给出与小能量攻击时机理解析的弹性被动容侵来提升系统对攻击的防御能力;然后,借助T-S模糊理论、时滞系统理论、新型Bessel-Legendre不等式等,推证得到系统鲁棒观测器及双重安全控制器的解析求解方法,使双重安全控制与通讯性能得到折衷协同提升;最后,通过实例仿真验证所提出方法的有效性.     

DoS攻击下网络化控制系统基于观测器的记忆型事件触发预测控制

本文研究了DoS攻击下网络化控制系统记忆型事件触发预测补偿控制问题. 首先, 由于网络带宽资源有限 和系统状态不完全可观测性, 引入了记忆型事件触发函数, 为观测器提供离散事件触发传输方案. 然后, 分析了网络 传输通道上发生的DoS攻击. 结合上述记忆型事件触发方案, 在控制节点设计一类新颖的预测控制算法, 节省网络 带宽资源并主动补偿DoS攻击. 同时, 建立了基于观测器的记忆型事件触发预测控制的闭环系统, 并且分析稳定性. 通过线性矩阵不等式(LMI)和Lyapunov稳定性理论, 建立了控制器、观测器和记忆型事件触发矩阵的联合设计方案, 并验证了该方案的可行性. 仿真结果表明, 该方案结合记忆型事件触发机制可以有效补偿DoS攻击, 节约网络带宽 资源.     

Decentralized Resilient H∞ Load Frequency Control for Cyber-Physical Power Systems Under DoS Attacks

This paper designs a decentralized resilient H_∞ load frequency control (LFC) scheme for multi-area cyber-physical power systems (CPPSs). Under the network-based control framework, the sampled measurements are transmitted through the communication networks, which may be attacked by energy-limited denial-of-service (DoS) attacks with a characterization of the maximum count of continuous data losses (resilience index). Each area is controlled in a decentralized mode, and the impacts on one area from other areas via their interconnections are regarded as the additional load disturbance of this area. Then, the closed-loop LFC system of each area under DoS attacks is modeled as an aperiodic sampled-data control system with external disturbances. Under this modeling, a decentralized resilient H_∞ scheme is presented to design the state-feedback controllers with guaranteed H_∞ performance and resilience index based on a novel transmission interval-dependent loop functional method. When given the controllers, the proposed scheme can obtain a less conservative H_∞ performance and resilience index that the LFC system can tolerate. The effectiveness of the proposed LFC scheme is evaluated on a one-area CPPS and two three-area CPPSs under DoS attacks.      

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.     

Resilient Time-Varying Formation-Tracking of Multi-UAV Systems Against Composite Attacks: A Two-Layered Framework

This paper studies the countermeasure design problems of distributed resilient time-varying formation-tracking control for multi-UAV systems with single-way communications against composite attacks,including denial-of-services(DoS)attacks,false-data injection attacks,camouflage attacks,and actuation attacks(AAs).Inspired by the concept of digital twin,a new two-layered protocol equipped with a safe and private twin layer(TL) is proposed,which decouples the above problems into the defense scheme ...     

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.     

列车控制系统的抗拒绝服务攻击弹性控制策略

当遭受拒绝服务(DoS)攻击时,分布式列车控制系统的弹性控制问题受到广泛关注.本文提出了一种基于分布式领导车状态观测器和障碍李雅普诺夫函数的弹性控制策略,不仅可以避免列车碰撞,同时实现了编队控制的目标.首先,给出了一种分布式的领导车状态观测器设计方法,用于实时估计领导车的状态.理论分析表明,在DoS攻击满足一定约束的条件下,该状态观测器的估计误差具有指数稳定特性.在此基础上,通过将列车碰撞避免问题转化为状态受限问题,提出一种基于障碍李雅普诺夫函数的状态受限控制律,解决了DoS攻击下确保碰撞避免的车队控制问题.最后,数值仿真证实了本文方法的有效性.     

Adaptive Dynamic Surface control of An electrohydraulic Actuator with Friction Compensation

In this paper, an adaptive nonlinear control scheme with a friction observer for position control of an electrohydraulic actuator is proposed. The observer based on the LuGre friction model is employed to compensate for the friction. Adaptation laws are used to handle parameter uncertainties in the actuator and friction model. The control law including dynamics of the observer is developed through a backstepping‐like dynamic surface control (DSC) technique. Experimental results have illustrated the success of the control scheme. The results also show that the adaptive DSC controller has better tracking performance than an adaptive backstepping and conventional PI controllers.     

流媒体服务DoS及DDoS攻击分析

针对流媒体RTSP的交互过程,指出流媒体服务具有遭受DoS及DDoS攻击的可能,通过实验验证该结论。提出一个基于位置隐藏和负载均衡的针对流媒体服务DoS及DDoS攻击的防御方案,对目前广为流行的视频点播、IPTV等流媒体应用具有普遍的借鉴意义。     

Secure Synchronization Control for a Class of Cyber-Physical Systems With Unknown Dynamics

This paper investigates the secure synchronization control problem for a class of cyber-physical systems (CPSs) with unknown system matrices and intermittent denial-of-service (DoS) attacks. For the attack free case, an optimal control law consisting of a feedback control and a compensated feedforward control is proposed to achieve the synchronization, and the feedback control gain matrix is learned by iteratively solving an algebraic Riccati equation (ARE). For considering the attack cases, it is difficult to perform the stability analysis of the synchronization errors by using the existing Lyapunov function method due to the presence of unknown system matrices. In order to overcome this difficulty, a matrix polynomial replacement method is given and it is shown that, the proposed optimal control law can still guarantee the asymptotical convergence of synchronization errors if two inequality conditions related with the DoS attacks hold. Finally, two examples are given to illustrate the effectiveness of the proposed approaches.      

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.     

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.     

基于DoS攻击能量分级的ICPS综合安全控制与通信协同设计

针对一类有限能量拒绝服务（denial of service,DoS）攻击与执行器故障共存的工业信息物理系统（industry cyber-physical system,ICPS）,研究了综合安全控制与通信协同设计问题。首先,考虑单侧网络遭受DoS攻击的情形,构建了ICPS综合安全控制架构,并从防御者的视角通过分析不...     

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...     

Encryption–decryption-based event-triggered consensus control for nonlinear MASs under DoS attacks

In this article, the consensus tracking problem is discussed for a class of discrete-time nonlinear multi-agent systems (MASs) subject to denial-of-service (DoS) attacks. The individual agents interact with each other via communication network whose topology is assumed to be time-varying and strongly connected. Two techniques are employed to deal with the network-induced complexities. On one hand, an event-triggering scheme is adopted to regulate the data transmission among agents with the purpose of making full utilization of the limited communication resources; and on the other hand, an encryption–decryption mechanism is designed with the aim to provide compensation, thereby mitigating the DoS attack effects. It is the objective of the addressed problem to develop a distributed model-free adaptive control law to enforce the MASs achieve desirable consensus performance. By using a specific projection algorithm in combination with a dynamic linearization method, the desired control protocol is formulated explicitly, whose effectiveness and applicability are demonstrated via an illustrative numerical example.     

DoS攻击下基于多率采样的多智能体系统安全一致性

本 文 研 究 了 一 类 带 有 多 率 采 样 的 线 性 多 智 能 体 系 统(Multiagent Systems, MASs)在 拒 绝 服 务(Denial-of-Service, DoS)攻击下的安全一致性控制问题, 其中DoS攻击通常阻断智能体之间的信息传输. 本文将多 率采样在网络化控制系统中的结果推广到了多智能体系统, 并考虑了非理想通信网络环境. 首先, 通过引入一个匹 配机制来同步由多率采样引起的智能体不同状态分量的采样数据. 然后, 在DoS攻击下, 针对带有多率采样的线 性MAS提出了一个基于多率采样的安全一致性控制器. 通过使用李雅普诺夫稳定性理论和切换系统方法, 获得了 包含DoS 攻击持续时间以及攻击频率的安全一致性充分条件. 最后, 给出了一个仿真例子来验证所提方法的有效 性, 并给出了多率采样与单率采样机制的性能对比分析.     

拒绝服务攻击下领导-跟随多智能体系统的均方一致性研究

针对带有过程噪声和测量噪声的领导-跟随多智能体系统,研究拒绝服务攻击下多智能体系统的一致性问题.首先,设计基于卡尔曼滤波的状态观测器,对智能体状态进行有效准确的估计;然后,基于预测控制理论提出一种基于状态估计信息的分布式预测控制算法,从而实现领导-跟随多智能体系统的均方一致性控制,并给出拒绝服务攻击环境下实现领导-跟随多智能体系统均方一致性的充分必要条件;最后,通过数值仿真验证所提出方法的正确性和有效性.     

WLAN中基于规范的自适应DoS攻击检测*

无线网络由于其传输介质及通信规程的特殊性,除了要面对有线网络中存在的各种拒绝服务（denial of service, DoS）攻击之外,还面临着一些在无线环境下特有的DoS攻击。针对由伪造协议会话中使用的管理帧和EAP帧发起的DoS攻击,提出了一种基于规范的自适应检测方法（WSBA）,为无线局域网所执行的安全协议建立在正常运行时的状态转移模型连同网络安全策略约束定义作为检测规范,作为检测此类DoS攻击的依据。给出了检测阈值的自适应调整算法,分析了算法参数设置对检测性能的影响。实验测试结果表明该方法是正确而有效的。     

Observer-based finite-time security fault-tolerant control for nonlinear multi-agent systems under byzantine adversaries

This article investigates the issue of security-based adaptive output feedback finite-time fault-tolerant control (FTC) for nonlinear multi-agent systems subjected to Byzantine attacks. In this work, the fuzzy logic systems are employed to approximate the unknown nonlinearities, and unmeasurable states are estimated by the designed state observer. In addition, a data selector is designed to detect extremely malicious data of the controlled system. Considering the actuator faults, a novel Nussbaum function is utilized to compensate for the uncertainties of attacks and intermittent failures. Then, by introducing first-order filter, an observer-based distributed adaptive output feedback finite-time security FTC algorithm is developed, which demonstrates all signals of the system are bounded, and the feasibility and effectiveness of the developed control scheme can be verified by simulation results.