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.     

基于观测器的周期拒绝服务攻击网络化系统动态事件触发控制

针对具有周期拒绝服务(DoS)攻击的网络化系统,设计一种基于观测器的具有动态事件触发策略的控制器.首先,通过DoS攻击对网络化系统的影响建立了DoS攻击模型,采用切换系统的方法,将具有DoS攻击的网络化系统分为DoS攻击活跃子系统和DoS攻击休眠子系统.对不可测的系统状态设计状态观测器,通过在静态事件触发中引入一个内部...     

具有DoS攻击非线性网络的动态事件触发控制

针对非线性网络控制系统存在的拒绝服务（DoS）攻击设计一种具有动态事件触发策略的H_∞安全控制器.首先,将DoS攻击引起的丢包影响作为触发条件的不确定性,针对这个不确定性以及在静态事件触发中引入一个内部动态参数,设计动态事件触发机制,在此基础上设计具有H_∞性能的安全控制器.然后,考虑网络通道中网络诱导时延对系统的影响,建立能够体现时延上下界信息的Lyapunov-Krasovskii泛函,依据Lyapunov稳定性理论、Young’s不等式、Schur补引理、单边Lipschitz条件、二次内有界和动态事件触发条件推导出系统存在安全控制器的条件,继续利用一些特殊导数,将双线性矩阵不等式转化为一组线性矩阵不等式,从而实现触发参数与反馈增益的协同设计,同时保证存在DoS攻击的安全性能.最后,通过一个数值例子验证所提方法的有效性.     

欺骗攻击下网络化系统事件触发安全控制

针对网络控制系统受欺骗攻击问题,提出了事件触发器与安全控制器协同设计策略。提出了离散事件触发机制,克服了连续事件触发机制需要新增专用硬件且需要复杂计算避免芝诺现象局限。建立了有机融合欺骗攻击、事件触发机制、网络诱导延时及外部扰动多约束参数的闭环系统时滞模型,推导出了欺骗攻击下事件触发控制系统渐近稳定的充分条件,得到了事件触发器与安全控制器的协同设计条件。仿真验证了方法的有效性。     

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.     

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.     

DoS攻击下多自主体系统的事件触发安全控制

针对拒绝服务(DoS)攻击下的时变多自主体系统,在有限域内研究事件触发安全一致性问题。在信息传输过程中,拒绝服务攻击同时存在于测量和控制通道中。将拒绝服务攻击看作是驻留时间切换机制,增广系统转化为包含一个稳定子系统和一个不稳定子系统的离散驻留时间切换系统。为提高通信资源利用率,采用状态依赖阈值的事件触发机制来更新控制输入信号。基于多Lyapunov函数方法,以线性矩阵不等式形式给出系统一致指数稳定且具有期望H∞性能的两个充分条件以及可行的控制器增益。仿真实例验证了发生拒绝服务攻击时,多自主体系统仍然可以实现安全一致性。     

事件触发双模分布式预测控制

本文针对有界扰动作用下的线性离散大系统,提出了事件触发双模分布式预测控制设计方法.利用输入状态稳定性(input-to-state stability,ISS)理论建立了仅与子系统自身信息相关的事件触发条件.只有子系统满足相应的事件触发条件,才进行状态信息的传输和分布式预测控制优化问题的求解,并与邻域子系统交互最优解作用下的关联信息.当子系统进入不变集时,采用状态反馈控制律进行镇定,并与进入不变集的邻域子系统不再交互信息.分析了算法的递推可行性和系统的闭环稳定性,给出了扰动的上界.最后,通过车辆控制系统对算法进行仿真验证,结果表明,本文提出的方法能够有效降低优化问题的求解次数和关联信息的交互次数,节约计算资源和通信资源.     

自适应事件触发网络化非线性系统滤波器设计

本文针对网络化非线性控制系统设计了基于自适应事件触发方案满足H∞性能的模糊滤波器.第一,提出新的自适应事件触发方案来决定数据包是否需要传输到通信网络中,从而提高网络资源利用率;第二,运用模糊线积分的方法,构建模糊李雅普诺夫泛函,避免求解隶属函数的时间微分;第三,利用Wirtinger不等式及倒凸引理结合的技术,得到滤波...     

无线网络化控制系统的功率感知事件触发策略及其闭环稳定性

本文研究了能量受限无线网络化控制系统的设计和分析问题.首先建立了无线网络化控制系统中通信传输时的数据误码率和丢包率间的定量关系,从而在通信功率与系统性能之间建立了联系.进而设计了基于事件触发策略和功率优化机制的智能控制器,该方法充分考虑了网络节能与控制系统性能表现两方面的要求,通过添加事件触发机制减少了系统的通信次数,并在此基础上以优化算法优化单次发送功率.随后,在随机稳定框架下给出了相应闭环系统稳定的充分性条件,在理论上证明了在该充分条件下,本文的设计能够在降低通信能耗的同时令系统维持预期的性能表现.最后数值例子证明了所提出方法的有效性.     

Resilient control for networked control systems with dynamic quantization and DoS attacks

In this article, the resilient control for networked control systems in the presence of denial-of-service (DoS) attacks is investigated in a sampled-data and dynamic quantization scheme. A novel dynamic quantization strategy is designed for signal transmissions from encoding systems to decoding systems, in which the quantized states are transmitted through networks with a risk of DoS attacks. An estimator is introduced to the design of control laws. Some sufficient conditions in terms of quantization levels, DoS attack duration and frequencies are given for the asymptotic stability of networked control systems. Furthermore, an event-triggered communication scheme is designed for signal transmissions in control channels to reduce network resource consumption. The Zeno behavior is excluded in the designed event-triggered communication scheme. The quantization levels can be adaptively adjusted according to real-time situations. Finally, the effectiveness of the proposed strategy is illustrated by simulations.     

拒绝服务攻击下网络化非线性系统的采样数据控制

本文研究了在拒绝服务攻击下网络化非线性系统的采样数据输出反馈控制问题.首先,为了避免使用完整的状态信息,在存在拒绝服务攻击的情况下设计了一种新颖的切换观测器.其次,同时考虑两个采样周期和拒绝服务攻击的影响,建立了一个新的切换增广系统模型,包括系统本身和误差系统.利用该模型和分段Lyapunov-Krasovskii泛函方法推导出保证切换增广系统是指数稳定的充分条件.进一步,利用线性矩阵不等式的解给出了观测器和控制器增益的共同设计方案.最后,通过仿真验证所提出控制方法的有效性.     

Security distributed state estimation for nonlinear networked systems against DoS attacks

This paper is concerned with security distributed state estimation for nonlinear networked systems against denial‐of‐service attacks. By taking the effects of resource constraints into consideration, an event‐triggered scheme and a quantization mechanism are employed to alleviate the burden of network. A mathematical model of distributed state estimation is constructed for nonlinear networked systems against denial‐of‐service attacks. Sufficient conditions ensuring the exponential stability of the estimation error systems are obtained by utilizing the Lyapunov stability theory. The explicit expressions of the designed state estimators are acquired in terms of the linear matrix inequalities. Finally, a numerical example is used to testify the feasibility of the proposed method.     

Dynamic event-triggered dissipative control of nonlinear networked control systems with deception attacks

For nonlinear networked control systems with deception attacks, the problem of dynamic event-triggered dissipative control is researched in this article. First, on the basis of nonlinear networked control systems model, a dynamic event triggered scheme is proposed to save impact of network bandwidth. Second, considering the impact of time delay, a networked time-delay system model under deception attacks is established. Third, by constructing a new and less conservative Lyapunov function, using linear matrix inequality and unilateral Lipschitz condition, we derive some new sufficient conditions to guarantee the asymptotically stability of nonlinear networked control systems and strictly $({\mathrm{\mathbb{Q}}}_1,{\mathrm{𝕊}}_1,{\mathrm{ℝ}}_1)$-dissipative performance. Besides, a cooperative design strategy of dynamic event triggered scheme parameters and controller gain is put forward. Finally, a simulation example is given to prove feasibility and rationality of the proposed strategy.     

Event-triggered model predictive control of switched systems with denial-of-service attacks

Observer-based model predictive control (MPC) for the discrete-time switched systems suffered by event-triggered mechanism and denial-of-service (DoS) attacks is discussed in this paper. We assume that the switch is slow enough and the attacker's energy is limited. To save network resources, an event-triggered mechanism is designed based on dwell time and triggered error. Under the coupled influence of attack and trigger, a complex mismatch of system mode and controller mode occurs, which brings difficulties to the transformation of MPC optimization problem. To address this problem, a new performance index coefficient is designed by using the increasing/decreasing law of Lyapunov function. On this basis, the transformation of the optimization problem is realized. Then, the controller gain and observer gain for the attack-free case are designed to guarantee the exponential convergence of the closed-loop system. In the presence of attacks, we obtain the upper bound of attack duty cycle, below which the exponential convergence of the system can still be archived. An example is illustrated at last to verify the validity of the main results.     

DoS攻击下多智能体系统无模型自适应迭代学习跟踪控制EI北大核心CSCD

针对周期性拒绝服务(DoS)攻击下多智能体系统有限时间趋同跟踪控制问题,本文提出了一种无模型自适应迭代学习控制(MFAILC)算法.假设多智能体系统具有固定拓扑结构,并且仅有部分智能体可获取到期望轨迹信息.在多智能体系统数据传输过程中,需要经由对数量化器进行量化处理.首先,使用伪偏导数将智能体系统动态线性化,处理过程中考虑符合伯努利分布的周期性DoS攻击现象,在此基础上设计了MFAILC控制算法,其次,采用压缩映射方法给出了一个在期望意义下保证跟踪误差收敛的充分条件,并在理论上证明了所提算法的收敛性.所提算法只需利用系统的输入输出数据就可完成趋同跟踪任务.最后,仿真结果验证了所提算法的有效性.     

Stability analysis on networked control systems under double attacks with predictive control

In this paper, stability of a networked control system under denial‐of‐service and false data injection attacks is analyzed with a predictive control method. To model denial‐of‐service attacks on the forward channel of networked control system, game theory is introduced for obtaining balanced results by denial‐of‐service frequency and duration. Then, measurement outputs of the networked control system are maliciously modified in the feedback channel. Under this double attack strategy, the stability of networked control system with predictive control is analyzed using a switched system method. By comparing three types of attack models, advantages of the double attacks are discussed to illustrate the necessity of this research. A numerical simulation is given to demonstrate effectiveness of the proposed methods on a networked control system under double attacks.     

网络控制系统中的时戳预测函数控制

传统预测函数控制算法不能有效处理网络控制系统中的随机延迟,为此提出了时戳预测函数控制算法.该算法使用时间戳来估计由网络引入的控制延迟,在预测系统未来输出时明确考虑了该延迟,然后借鉴传统预测函数控制算法的基本策略,得到了适用于网络控制系统的控制规律.进一步由TrueT im e工具箱搭建了网络控制系统仿真平台,对比了时戳预测函数控制算法和传统预测函数控制算法.仿真结果表明随着网络引入延迟的增大,时戳预测函数控制算法给出控制品质明显优越于传统预测函数控制算法.     

Event-triggered containment control for multi-agent systems under hybrid cyber attacks

This paper studies event-triggered containment control problem of multi-agent systems (MASs) under deception attacks and denial-of-service (DoS) attacks. First, to save limited network resources, an event-triggered mechanism is proposed for MASs under hybrid cyber attacks. Different from the existing event-triggered mechanisms, the negative influences of deception attacks and DoS attacks are considered in the proposed triggering function. The communication frequencies between agents are reduced. Then, based on the proposed event-triggered mechanism, a corresponding control protocol is proposed to ensure that the followers will converge to the convex hull formed by the leaders under deception attacks and DoS attacks. Compared with the previous researches about containment control, in addition to hybrid cyber attacks being considered, the nonlinear functions related to the states of the agents are applied to describe the deception attack signals in the MAS. By orthogonal transformation of deception attack signals, the containment control problem under deception attacks and DoS attacks is reformulated as a stability problem. Then, the sufficient conditions on containment control can be obtained. Finally, a set of simulation example is used to verify the effectiveness of the proposed method.     

Model predictive control for networked control systems

This paper investigates the problem of model predictive control for a class of networked control systems. Both sensor‐to‐controller and controller‐to‐actuator delays are considered and described by Markovian chains. The resulting closed‐loop systems are written as jump linear systems with two modes. The control scheme is characterized as a constrained delay‐dependent optimization problem of the worst‐case quadratic cost over an infinite horizon at each sampling instant. A linear matrix inequality approach for the controller synthesis is developed. It is shown that the proposed state feedback model predictive controller guarantees the stochastic stability of the closed‐loop system. Copyright © 2008 John Wiley & Sons, Ltd.