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.     

具有时变采样周期网络控制系统的严格耗散控制

研究具有时变采样周期和数据丢包的网络控制系统的渐近稳定和严格耗散控制问题.针对采样周期时变且在标称周期上下波动,数据丢包数有界,利用参数不确定的方法,网络控制系统建模为一类带有参数不确定的离散时滞系统.构造一个改进的李雅普诺夫-卡拉索夫斯基函数,基于线性矩阵不等式方法及Jensen不等式方法,给出系统严格(Q,S,R)-耗散的充分条件,得到控制器的设计方法.数值实例表明所提出的方法具有较小的保守性,同时也减少了计算量.     

具有随机丢包的网络控制系统的镇定

研究具有随机丢包的网络控制系统(NCS)的镇定问题.同时考虑传感器节点到控制器节点(S/C)和控制器节点到执行器节点(C/A)的随机丢包,并分别对这两种丢包现象建模.基于Lyapunov稳定性理论,得到闭环系统全局均方渐近稳定的充分条件.进一步利用线性矩阵不等式(LMI)方法,得到状态反馈控制律的增益矩阵.数值仿真算例验证了所得结果的有效性.     

Stability analysis of networked control systems with time-varying sampling periods

In this paper, we present an interval model of networked control systems with time-varying sampling periods and time-varying network-induced delays and discuss the problem of stability of networked control systems using Lyapunov stability theory. A sufficient stability condition is obtained by solving a set of linear matrix inequalities. In the end, the illustrative example demonstrates the correctness and effectiveness of the proposed approach.     

具有有界时滞的网络控制系统的镇定

针对具有有界时滞且时滞上界大于一个采样周期的网络控制系统,研究了系统建模和状态反馈镇定问题.在分析有界时滞的所有可能性的基础上,提出一种能够用于处理时变控制律问题的网络控制系统数学模型,进而将该系统的镇定问题转化为镇定一系列模型的鲁棒控制问题.根据 Lyapunov 方法,给出了保证闭环系统稳定的状态反馈控制器.仿真算例验证了所提出方法的有效性.     

网络控制系统时变采样周期的建模与切换控制*

针对具有双边随机时延和丢包的网络控制系统,首先采用了主动时变采样周期的方法,利用事件和时间驱动相结合方式,传感器的采样周期可实时地跟随网络延时和丢包的变化而改变,克服了长时延和数据包错序的问题。然后将系统建立为统一的切换系统模型,结合基于平均驻留时间的方法,给出了系统状态满足指数稳定的条件,并且描述了其指数衰减率和丢包率之间的定量关系。最后通过数值例仿真验证了本文所提方法的有效性。     

基于信噪比受限通道的网络控制系统镇定

研究了同时考虑通信和网络特性的线性系统镇定问题.首先针对连续时间网络控制系统,使用线性矩阵不等式方法得到了系统镇定所需要的最小信噪比;然后将问题推广到一类更为复杂的离散时间异构网络控制系统并得到了相似的结论.其中建立的多传感器随机时滞模型很好地刻画了token-passing总线控制网络,它更具有实际意义;最后通过数值例子对以上理论进行了仿真验证,有效表明了系统镇定时被控对象不稳定极点、网络时滞和信噪比之间的关系.     

Quantitative analysis and synthesis for networked control systems with non‐uniformly distributed packet dropouts and interval time‐varying sampling periods

This paper is concerned with quantitative analysis and synthesis for a networked control system under simultaneous consideration of non‐uniformly distributed packet dropouts, interval time‐varying sampling periods and network‐induced delays. A new packet dropout separation method is proposed to separate packet dropouts from the lump sum of network‐induced delays and packet dropouts. An interval time‐varying sampling period approach, which is more general than a switched sampling period approach, is presented to model the variation of the sampling period. Then a packet dropout decomposition‐based Lyapunov functional is constructed to drive some stability criteria. Based on these stability criteria, a state feedback controller is designed to asymptotically stabilize the networked system in the sense of mean‐square. Numerical examples are given to illustrate the effectiveness of the obtained results. Copyright © 2013 John Wiley & Sons, Ltd.     

数据包丢失网络控制系统的保成本控制

针对同时具有不确定短时延及数据包丢失的网络控制系统,引入丢包补偿器补偿丢包对系统的影响,当发生数据包丢失时,控制器采用丢包补偿器产生的预估状态代替系统的真实状态计算控制量。同时考虑不确定短时延的影响,将网络控制系统建模为一类具有参数不确定的离散切换系统．利用线性矩阵不等式(linear matrix inequality,简称LMI)方法给出了系统的保成本控制器和丢包补偿器的协同设计方法,仿真结果表明所提出的方法是有效的。     

具有时延的网络控制系统控制器设计

针对一类存在随机时延的网络控制系统,传感器采用时间驱动,控制器和执行器采用事件驱动,提出了一种新的具有随机时延的网络控制系统的建模方法-离散模糊T-S模型,在此模型的基础上应用并行分布补偿（PDC）原理设计了模糊控制器。应用Lyapunov定理和线性矩阵不等式（LMI）方法,研究了系统的稳定性问题,给出基于LMI的状态反馈模糊控制器的设计方法。通过仿真实例验证控制方法能够保证系统稳定。     

Observer-based output feedback control of networked control systems with non-uniform sampling and time-varying delay

This paper investigates the problem of observer-based output feedback control for networked control systems with non-uniform sampling and time-varying transmission delay. The sampling intervals are assumed to vary within a given interval. The transmission delay belongs to a known interval. A discrete-time model is first established, which contains time-varying delay and norm-bounded uncertainties coming from non-uniform sampling intervals. It is then converted to an interconnection of two subsystems in which the forward channel is delay-free. The scaled small gain theorem is used to derive the stability condition for the closed-loop system. Moreover, the observer-based output feedback controller design method is proposed by utilising a modified cone complementary linearisation algorithm. Finally, numerical examples illustrate the validity and superiority of the proposed method.     

Stabilization of nonlinear networked probabilistic interval delay systems with sensor random packet dropout

In this paper, the problem of stabilization for nonlinear networked systems with probabilistic interval delay and sensor random packet dropout is investigated. By employing the information of probabilistic distribution of time‐varying delay and considering random sensor packet dropout with compensation, the nonlinear stochastic delayed system model is established. Based on the obtained model, by choosing an appropriate Lyapunov function and utilizing a new discrete Jensen‐type inequality, sufficient conditions are derived to obtain the relation of the maximum allowable delay bound, delay interval occurrence rate and packet dropout rate to the stochastic stability of nonlinear networked control systems. Two kinds of design procedures for output feedback controller are also presented in terms of solving corresponding linear matrix inequalities. Numerical examples are provided to illustrate the effectiveness and applicability of proposed techniques. Copyright © 2011 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society     

具有随机长时延的网络控制系统保性能控制

本文研究了一类具有随机长时延离散时间网络控制系统(NCSs)的建模和保性能控制问题.用两个马尔可夫链分别来描述反馈通道和前向通道的网络诱导时延,基于采用现有最新数据的原则,将闭环NCS建模成一个与当前时刻和过去时刻网络诱导时延有关的马尔可夫随机时滞系统.应用线性矩阵不等式技术和李亚普诺夫方法得到了闭环NCS随机稳定且具有二次性能指标上界的充分条件,并给出了状态反馈保性能控制器的设计方法.最后,通过数值算例验证了本文方法的有效性.     

基于脉冲微分系统模型的有损网络控制系统研究

针对闭环网络控制系统,在考虑网络数据传输可能发生丢包的情况下,提出了一类切换系统模型,并在此基础上导出了一类脉冲微分系统模型.从数学上严格分析了该模型的合理性,并利用驻留时间的概念得到了此系统模型的稳定性条件,进一步研究了能够忍受一定程度的数据丢包的稳定化控制器设计问题.最后给出了一个具体示例.     

有界随机测量时滞的网络控制系统的最优估计

在假设测量没有丢包的情况下, 研究了带有随机测量时滞的网络控制系统的最优估计问题. 利用已知的时 滞分布概率, 建立新的模型来描述随机时滞测量. 进一步将带有时滞的测量等价成每个通道是单时滞的多通道测 量, 从而利用新息重组方法, 通过求解黎卡提方程求解最优估计器. 最后给出仿真实例验证了该算法的有效性.     

带有随机时延的非线性网络控制系统的输出反馈镇定

考虑了一类非线性网络控制系统的输出反馈镇定问题.通过齐次马尔可夫链来描述采样器-控制器和控制器.执行器的时延,将网络控制系统建模为带跳非线性系统.利用Lyapunov方法和线性矩阵小等式技巧,得到了闭环系统随机稳定的充分条件,并给出了镇定控制器的设计方法.     

Convergence properties of two networked iterative learning control schemes for discrete-time systems with random packet dropout

This paper addresses convergence issue of two networked iterative learning control (NILC) schemes for a class of discrete-time nonlinear systems with random packet dropout occurred in input and output channels and modelled as 0–1 Bernoulli-type random variable. In the two NILC schemes, the dropped control input of the current iteration is substituted by the synchronous input used at the previous iteration, whilst for the dropped system output, the first replacement strategy is to replace it by the synchronous pre-given desired trajectory and the second one is to substitute it by the synchronous output used at the previous iteration. By the stochastic analysis technique, we analyse the convergence properties of two NILC schemes. It is shown that under appropriate constraints on learning gain and packet dropout probabilities, the tracking errors driven by the two schemes are convergent to zero in the expectation sense along iteration direction, respectively. Finally, illustrative simulations are carried out to manifest the validity and effectiveness of the results.     

具有数据包丢失的网络控制系统保性能控制

本文研究了一类具有数据包丢失的网络控制系统(NCSs)的建模和保性能控制问题.通过用两个马尔可夫链分别来描述前向通道和反馈通道的丢包过程,将闭环网络控制系统建模成具有两个模式的马尔可夫随机切换系统.基于线性矩阵不等式技术和李亚普诺夫方法得到了闭环系统随机稳定的充分条件,并给出了状态反馈保性能控制器的设计方法.最后通过数值算例验证本文结果的有效性.     

Quantized stabilization of networked control systems with actuator saturation

In this paper, we investigate the problems of stabilization of networked control systems with quantization and actuator saturation via delta operator approach. The definition of the domain of attraction for delta operator systems is introduced to analyze the stochastic stability of the closed‐loop networked control systems. The quantizer is a uniform one with arbitrary quantization regions, and the packet dropout process is modeled as a Bernoulli process. On the basis of the zoom strategy and Lyapunov theory in delta domain, sufficient conditions are given for the closed‐loop delta operator systems to be mean square stable, and the feedback controllers are designed to ensure the stability of networked control systems. A single link direct joint driven manipulator model is presented to show the effectiveness of the main results. Copyright © 2016 John Wiley & Sons, Ltd.     

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.