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.     

关于Sontag-Type控制的注记

基于控制李雅普诺夫函数的Sontag-Type控制是仿射系统鲁棒镇定中的重要控制律.首先揭示该控制律本质上是一种变结构控制且闭环的切换面总可达,受此启发并为了相对容易地构造控制李雅普诺夫函数,运用零状态可检测概念定义弱控制李雅普诺夫函数,并证明了基于弱控制李雅普诺夫函数的Sontag-Type控制的优化镇定性.文中还证明,在温和条件下,基于弱控制李雅普诺夫函数的Sontag＿Type控制为仿射系统的输入到状态镇定控制.     

航天器全状态约束输出反馈控制

针对无角速度测量的刚性航天器姿态跟踪问题,提出一种全状态约束输出反馈控制方法.建立修正罗德里格参数描述的系统模型,提出能够适用于约束与非约束情况的改进型障碍李雅普诺夫函数(MBLF),拓展传统对数型障碍李雅普诺夫函数的适用范围.构造二阶辅助系统,将控制输入和饱和输入之间的差作为构造系统的输入,进而产生信号以补偿饱和的影响.设计状态观测器估计未知状态量,并结合反步法设计输出反馈控制律,保证系统全状态约束性能和姿态跟踪精度.通过李雅普诺夫稳定性分析证明姿态观测误差和跟踪误差能够达到一致最终有界.仿真结果验证所提方法的有效性.     

具有未建模动态的互联大系统事件触发自适应模糊控制

针对一类具有未建模动态及执行器故障的非严格反馈非线性互联大系统, 提出一种基于事件触发机制的模糊分散自适应输出反馈控制算法. 首先, 通过设计模糊状态观测器估计系统中不可测的状态, 并引入李雅普诺夫函数约束未建模动态. 然后, 提出一种基于事件触发机制的自适应容错控制器补偿多个执行器故障产生的影响. 最后, 利用障碍李雅普诺夫函数实现对系统输出的约束, 并证明闭环系统中所有信号均是半全局一致最终有界的, 且设计的事件触发机制可以避免Zeno行为. 数值仿真结果验证所提出设计方案的可行性及有效性.     

带有输出约束的柔性关节机械臂预设性能自适应控制

针对带有输出约束和模型不确定的柔性关节机械臂系统,提出一种基于时变障碍李雅普诺夫函数的预设性能自适应控制方法.通过构造指数衰减的时变约束边界,提出时变正切型障碍李雅普诺夫函数,能够同时适用于约束与非约束情况,进而拓宽传统对数型障碍李雅普诺夫函数的适用范围.此外,通过预先设置时变边界函数的相关参数,使得系统输出在初始阶段...     

输出约束条件下一类热传导方程的边界控制

约束问题普遍存在于物理系统中,如何解决分布参数系统的约束问题还没有有效的方法.本文以一类非齐次的热传导方程作为研究对象,设计了一种新型的边界控制方法来稳定系统状态并解决热传导方程的约束问题.为此首先简要地介绍了由偏微分方程和常微分方程共同描述的热传导方程.然后,在未知的分布式外界扰动的影响下,设计一种新型的基于障碍-积分型李雅普诺夫函数的边界控制方法.此方法是基于原始的分布参数系统模型,没有任何的模型简化,因此有效地避免了溢出不稳定问题.本文采用李雅普诺夫方法证明系统稳定性并保证系统的边界输出约束在一定的范围内.最后采用有限差分法进行仿真验证,仿真结果进一步证明了所提出的边界控制方法的有效性.     

基于李雅普诺夫量子系统控制方法的状态调控

从多方面对基于李雅普诺夫的量子系统控制方法进行了系统深入地研究, 包括该方法与最优控制的关系; 李雅普诺夫函数与性能指标之间的关系; 几种常用李雅普诺夫函数下的控制所能解决的问题, 适用范围和所存在的问题等. 在此基础上, 结合量子系统本身所具有的特点, 分别针对本征态, 叠加态和混合态的制备与调控目标, 总结出多种不同控制问题的改进方案. 对不同改进方案的设计思想, 所能解决的问题, 物理意义及其适用范围等进行剖析, 系统化了一套基于李雅普诺夫稳定性理论对量子系统进行状态调控的设计方法.     

李雅普诺夫函数优化:正交矩阵构造方案EI北大核心CSCD

本文研究了李雅普诺夫函数的优化问题.提出了一种正交矩阵构造方案,用于求解黎卡提不等式中的最优李雅普诺夫函数.通过分析系统H_(∞)范数的几何特征,本文将黎卡提不等式转换为近似等式,进而给出了最优李雅普诺夫函数的存在条件.基于所给最优李雅普诺夫函数存在条件,所提正交矩阵构造方案利用旋转变换,将非线性方程组的求解问题转换为幅值和角度的线性优化问题,进而实现李雅普诺夫函数参数的优化.研究结果弥补了目前的研究无法求解最优李雅普诺夫函数的不足,对系统性能分析和非保守控制的设计具有建设性.算例验证了所提正交矩阵构造方案的有效性.     

DoS攻击下一类二阶多智能体系统的安全分组一致性研究

针对拒绝服务(denial-of-service, DoS)攻击下一类二阶多智能体系统的安全分组一致性协同控制问题,区别于同类工作,在非周期性多信道独立的攻击场景下,基于复杂系统中智能体间的合作与竞争交互,提出一种新的带有状态估计器的安全分组一致性控制协议.在该协议的作用下,首先,给出DoS攻击持续时间的约束条件,通过设计合适的李雅普诺夫函数,结合求解代数黎卡提方程得到不同攻击模式下信道的衰减率;然后,通过引入与各个信道对应的等效衰减率,克服所得衰减率与信道难以匹配的问题,并给出系统的稳定性判据;最后,通过数值实验验证理论分析所得结论的正确性和有效性.     

状态约束下单连杆机械臂输出反馈自适应跟踪控制

研究了一类具有全状态约束且状态不可测的单连杆机械手跟踪控制问题。尽管现有的输出反馈跟踪控制方法可以有效地解决状态不可测情况下的机械手位置跟踪控制问题,但未考虑基于操作安全等因素设定的状态受限。同时,系统状态不可测也为实现状态受限带来了挑战。因此,考虑在系统全状态受限并且仅机械手位置可测情况下的输出反馈跟踪控制器设计问题。首先,构造了一个模糊状态观测器来估计不可测状态;然后,通过融合新的状态变换函数和动态表面控制方法,建立了一种基于观测器的自适应模糊控制策略,并利用李雅普诺夫稳定性理论,证明了位置跟踪误差将收敛到零点附近任意小的邻域之内,且系统中的状态永远不会超越约束条件;最后,通过数值模拟验证了所提方法的可行性。     

Resilient and Safe Platooning Control of Connected Automated Vehicles Against Intermittent Denial-of-Service Attacks

Connected automated vehicles (CAVs) serve as a promising enabler for future intelligent transportation systems because of their capabilities in improving traffic efficiency and driving safety, and reducing fuel consumption and vehicle emissions. A fundamental issue in CAVs is platooning control that empowers a convoy of CAVs to be cooperatively maneuvered with desired longitudinal spacings and identical velocities on roads. This paper addresses the issue of resilient and safe platooning control of CAVs subject to intermittent denial-of-service (DoS) attacks that disrupt vehicle-to-vehicle communications. First, a heterogeneous and uncertain vehicle longitudinal dynamic model is presented to accommodate a variety of uncertainties, including diverse vehicle masses and engine inertial delays, unknown and nonlinear resistance forces, and a dynamic platoon leader. Then, a resilient and safe distributed longitudinal platooning control law is constructed with an aim to preserve simultaneous individual vehicle stability, attack resilience, platoon safety and scalability. Furthermore, a numerically efficient offline design algorithm for determining the desired platoon control law is developed, under which the platoon resilience against DoS attacks can be maximized but the anticipated stability, safety and scalability requirements remain preserved. Finally, extensive numerical experiments are provided to substantiate the efficacy of the proposed platooning method.      

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.     

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.     

Dynamic-estimator-based adaptive secure containment control for constrained nonlinear multi-agent systems under denial-of-service attacks

This article concentrates upon the adaptive secure containment control problem for a class of uncertain nonlinear multi-agent systems with the output constraint requirements under denial-of-service (DoS) attacks. At first, to overcome the difficulty that the tracking performance of the nonlinear multi-agent systems under the DoS attacks is disturbed seriously, a novel adaptive secure containment control approach is presented by applying a DoS attacks detection mechanism and introducing the barrier Lyapunov functions, which enables the system to achieve the security control objective that the output of each agent eventually converges to the convex hull spanned by the dynamic leaders' outputs, while never violating the output constraints. Then, a state estimator is designed, which reconstructs the immeasurable states of the multi-agent systems and approximates the completely unknown nonlinearities arising from the agents. In addition, the dynamic surface control technique is used to solve the “explosion of complexity” problem. It is demonstrated that the proposed anti-attack controller ensures that all the signals of the closed-loop system are semi-globally uniformly ultimately bounded. Finally, a simulation example is provided to illustrate the effectiveness of the theoretical results.     

Adaptive fault-tolerant control for multiple Euler–Lagrange systems considering time delays and output constraints

Considering the existence of communication delays, the adaptive fault-tolerant control problems for constrained multiple Euler–Lagrange systems are considered in this paper. First, a communication delays observer is utilized to enable all followers can acquire the leader's state information. Second, based on neural network technique, two distributed coordinated control schemes are designed to make every follower can track the leader. Compared with the first control algorithm, the adaptive fault-tolerant control problem is further considered in the second control algorithm. The proposed algorithm can simultaneously compensate the actuator bias faults and the partial loss of actuation effectiveness faults. At the same time, a tan-type barrier Lyapunov function is used to constrain the tracking errors of all followers and the leader. Finally, the simulations show the effectiveness of the proposed control schemes.     

Robust event‐triggered model predictive control for cyber‐physical systems under denial‐of‐service attacks

This paper investigates the resilient control problem for constrained continuous‐time cyber‐physical systems subject to bounded disturbances and denial‐of‐service (DoS) attacks. A sampled‐data robust model predictive control law with a packet‐based transmission scheduling is taken advantage to compensate for the loss of the control data during the intermittent DoS intervals, and an event‐triggered control strategy is designed to save communication and computation resources. The robust constraint satisfaction and the stability of the closed‐loop system under DoS attacks are proved. In contrast to the existing studies that guarantee the system under DoS attacks is input‐to‐state stable, the predicted input error caused by the system constraints can be dealt with by the input‐to‐state practical stability framework. Finally, a simulation example is performed to verify the feasibility and efficiency of the proposed strategy.     

混合攻击下直流微电网的FDI估计与模糊控制联合设计

研究基于T-S模糊模型的直流微电网(DC-MG)系统在拒绝服务(DoS)和虚假数据注入(FDI)混合攻击下的协同估计控制框架.考虑网络化T-S模糊模型和并行分布补偿(PDC)模糊控制规则中的非均匀时间尺度,建立DC-MG系统的T-S模型.为了放宽现有的DoS攻击模型通常假定攻击的频率和持续时间均有限的要求,在攻击信号的休眠和活跃期的已知范围内提出一种新的DoS攻击模型.同时,构造一个切换脉冲观测器来估计由外部动态系统产生的未知FDI攻击信号.然后,利用依赖于攻击参数的时变Lyapunov函数方法,导出系统在混合攻击下的指数稳定性判据.此外,基于线性矩阵不等式给出了模糊控制器和FDI攻击观测器的联合设计方法.最后,通过案例研究验证了所提出理论结果的有效性.     

Fully Distributed Resilient Cooperative Control of Vehicular Platoon Systems Under DoS Attacks

Dear Editor, This letter is concerned with distributed resilient platoon control of multiple vehicles subject to denial-of-service (DoS) attacks. In order to ac...     

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.     

控制方向未知的全状态约束非线性系统的鲁棒自适应跟踪控制

针对一类控制方向未知的含有时变不确定参数和未知时变有界扰动的全状态约束非线性系统,本文提出了一种基于障碍Lyapunov函数的反步自适应控制方法.障碍Lyapunov函数保证了系统状态在运行过程中始终保持在约束区间内;Nussbaum型函数的引入解决了系统控制方向未知的问题;光滑投影算法确保了不确定时变参数的有界性.障碍Lyapunov函数、Nussbaum型函数及光滑投影算法与反步自适应方法的有效结合首次解决了控制方向未知的全状态约束非线性系统的跟踪控制问题.所设计的自适应鲁棒控制器能在满足状态约束的前提下确保闭环系统的所有信号有界.通过恰当地选取设计参数,系统的跟踪误差将收敛于0的任意小的邻域内.仿真结果表明了控制方案的可行性.