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.     

Robust reliable sampled-data control for switched systems with application to flight control

This paper addresses the robust reliable stabilisation problem for a class of uncertain switched systems with random delays and norm bounded uncertainties. The main aim of this paper is to obtain the reliable robust sampled-data control design which involves random time delay with an appropriate gain control matrix for achieving the robust exponential stabilisation for uncertain switched system against actuator failures. In particular, the involved delays are assumed to be randomly time-varying which obeys certain mutually uncorrelated Bernoulli distributed white noise sequences. By constructing an appropriate Lyapunov–Krasovskii functional (LKF) and employing an average-dwell time approach, a new set of criteria is derived for ensuring the robust exponential stability of the closed-loop switched system. More precisely, the Schur complement and Jensen's integral inequality are used in derivation of stabilisation criteria. By considering the relationship among the random time-varying delay and its lower and upper bounds, a new set of sufficient condition is established for the existence of reliable robust sampled-data control in terms of solution to linear matrix inequalities (LMIs). Finally, an illustrative example based on the F-18 aircraft model is provided to show the effectiveness of the proposed design procedures.     

Observer-based controller design for networked control systems with sensor quantisation and random communication delay

This article addresses the study of observer-based controller design for network-based control systems in the presence of output quantisation and random communication delay simultaneously. In the communication channel, the output measurement are quantised before transmission, and two kinds of network-induced delays are taken into account simultaneously: (i) random delay from sensor to controller and (ii) random delay from controller to actuator. These two types of random delays are modelled as two independent Bernoulli distributed white sequences. The observer-based controller is synthesised to stabilise the networked closed-loop system in the sense of stochastic stability. Sufficient conditions for the existence of the controller are provided by stochastic Lyapunov method. An illustrative numerical example is employed to demonstrate the applicability and flexibility of the proposed design strategy.     

变采样网络控制系统的鲁棒控制

对于线性时不变控制对象,在控制器和控制对象都采用时间-事件驱动时系统就变成便采样网络控制系统,当网络时延不确定时,在小于或者等于一个变采样周期时,基于动态输出反馈对变采样网络控制系统进行建模,使用李雅普诺夫方法和线性矩阵不等式研究了系统的鲁棒稳定性,并设计了鲁棒控制器,最后给出实例证明在鲁棒控制器的控制下系统稳定。     

网络化控制系统中鲁棒控制器的设计与优化

针对网络化控制系统,提出了新型的延迟状态变量模型,考虑到模型的不确定因素和外 部扰动,推出了鲁棒控制器存在的条件,并给出了该控制器设计和性能优化的方法。仿真结果表明, 该控制器对所有允许的网络延迟、模型不确定性和外部扰动,具有良好的性能。     

不确定非线性网络化系统的鲁棒H_∞控制

用T-S(Takagi-Sugeno)模糊方法研究了带有参数不确定的非线性网络化系统的鲁棒控制.首先,考虑到诱导时延和数据丢包等网络因素的影响,基于事件驱动的保持器的更新序列建立闭环反馈系统的采样模型,并将其转化为状态中附加两个时滞变量的连续T-S模糊系统.然后,利用时滞系统方法,分析不确定闭环模糊系统的鲁棒H∞性能,并设计相应的鲁棒H∞模糊控制器.最后,仿真例子表明了方法的有效性.     

Robust global stabilisability by means of sampled-data control with positive sampling rate

This work proposes a notion of robust reachability of one set from another set under constant control. This notion is used to construct a control strategy, involving sequential set-to-set reachability, which guarantees robust global stabilisation of non-linear sampled data systems with positive sampling rate. Sufficient conditions for robust reachability of one set from another under constant control are also provided. The proposed method is illustrated through a number of examples, including the study of the sampled-data stabilisation problem of the chemostat.     

多回路网络化控制系统中优化采样频率的确定

在多回路网络化控制系统中，通讯资源的共享和网络传输的时延为系统分析和设计带来新的问题．运用非线性规划理论，分析和推导了多回路网络化控制系统中采样频率优化问题，并由推导过程归纳出易于计算机编程实现的工程化求解方法．通过仿真示例验证了所提出方法的有效性．     

具有通信约束的网络控制系统动态调度与H∞控制协同设计

针对一类具有通信约束的随机时延网络控制系统,提出一种基于试一次丢弃(try-once-discard,TOD)动态调度策略与鲁棒H∞控制器协同设计的方法.考虑通信约束和随机时延的影响,将系统建模为一类具有参数不确定性的离散切换系统,并采用切换系统和Lyapunov稳定性理论,给出了TOD调度策略下使闭环系统渐近稳定的鲁棒H∞控制器设计方法.最后通过仿真验证了方法的有效性.     

Self-triggered sampling control for networked control systems with delays and packets dropout

In this paper, a self-triggered sampling (STS) scheme is proposed for a networked control system with delays and packets dropout. Sampling periods are given based on a probability of successful transmission for packets by signal-to-interference-and-noise ratio measured via quality-of-service. The networked control system is described as a switched delta operator system by the STS scheme. Sufficient conditions of stability for the network control system with delays and packets dropout are given with average dwell time in terms of linear matrix inequalities. A numerical example is given to illustrate the effectiveness and potential for the developed techniques.     

Robust reliable H∞ control design for networked control systems with nonlinear actuator faults and randomly missing measurements

In this paper, the robust reliable H_∞ controller is designed for the problem of nonlinear actuator fault case in the uncertain networked control systems with randomly occurring missing data. More precisely, the occurrence of missing measurements is modeled by a stochastic variable in terms of Bernoulli random distribution. Also, the consideration of a nonlinear term in the input control scheme is a novel work for the proposed model. Suitable robust reliable design of control for a practical actuator fault model is constructed to guarantee the asymptotic stability of the system with H_∞ performance level. A new form of Lyapunov‐Krasovskii functional with triple integral terms are formulated, and the reciprocally convex technique is utilized to establish the sufficient stability criterion in the form of linear matrix inequalities. Finally, the effectiveness of the proposed control method is shown through numerical examples, and we can confirm that the derived condition attained less conservatism than the existing results.     

网络控制系统的鲁棒L1跟踪控制

将L1性能约束引入网络控制系统中,研究具有时延和不确定性的网络控制系统的模型参考输出跟踪问题。基于线性矩阵不等式方法推出了该网络控制系统的稳定性和控制器设计的充分条件,并将控制器的设计转化为一个凸优化的求解问题。所设计的控制器能够保证相对于所有峰值有界的外界扰动信号,网络控制系统具有L1性能约束水平。仿真实例证实了该设计方法的有效性。     

Robust stabilisation control for discrete-time networked control systems

We consider the analysis and synthesis of discrete-time networked control systems (NCSs), where the plant has additive uncertainty and the controller is updated with the sensor information at stochastic time intervals. It is shown that the problem is linked to H_∞-control of linear discrete-time stochastic systems and a new small gain theorem is established. Based on this result, sufficient conditions are given for ensuring mean square stability of the NCS, and the genetic algorithm is utilised to design the controller of the NCS based on a linear matrix inequality technique. An illustrative example is given to demonstrate the effectiveness of our proposed method.     

分布式网络化控制系统故障诊断方法的研究

为了避免分布式网络化控制系统由于网络负载过大而造成的时延和丢包问题,引入基于包的传输机制,并针对此特殊结构设计中心故障诊断单元,在诊断单元设计中,由于各子系统工作周期不同以及传输包的大小不同,将系统看作多速率采样系统,采用提升技术获得系统的离散模型.在此基础上设计状态观测器,实现分布式网络化控制系统的故障诊断.最后通过仿真验证了所提出方法的有效性.     

网络化制造系统访问控制框架

建立SDACM对象模型的基础上,提出一个网络化制造系统的访问控制框架,研究了访问控制框架的工作流程以及框架与系统其他安全部件的关系。基于该框架开发的网络化制造原型系统在某企业应用中表明该框架能够满足网络化制造系统需求。     

带有输出传输时延的网络化控制系统基于观测器的FDI设计(英文)

将网络控制系统(NCS)看成一个具有输出时延的采样控制系统, 并建立了其数学模型. 接着构造了一个故障观测器, 产生了系统故障的指示器残差. 然后在此基础上介绍了一种故障检测和分离 (FDI)的方法, 总结了FDI观测器的设计算法. 最后, 一个实例证明了此方法的可行性.     

带有输出传输时延的网络化控制系统基于观测器的FDI设计

将网络控制系统(NCS)看成一个具有输出时延的采样控制系统, 并建立了其数学模型. 接着构造了一个故障观测器, 产生了系统故障的指示器残差. 然后在此基础上介绍了一种故障检测和分离 (FDI)的方法, 总结了FDI观测器的设计算法. 最后, 一个实例证明了此方法的可行性.     

Delay-dependent resilient-robust stabilisation of uncertain networked control systems with variable sampling intervals

This work is concerned with the robust resilient control problem for uncertain networked control systems (NCSs) with variable sampling intervals, variant-induced delays and possible data dropouts, which is seldom considered in current literature. It is mainly based on the continuous time-varying-delay system approach. Followed by the nominal case, delay-dependent resilient robust stabilising conditions for the closed-loop NCS against controller gain variations are derived by employing a novel Lyapunov–Krasovskii functional which makes good use of the information of both lower and upper bounds on the varying input delay, and the upper bound on the variable sampling interval as well. A feasible solution of the obtained criterion formulated as linear matrix inequalities can be gotten. A tighter bounding technique is presented for acquiring the time derivative of the functional so as to utilise many more useful elements, meanwhile neither slack variable nor correlated augmented item is introduced to reduce overall computational burden. Two examples are given to show the effectiveness of the proposed method.