Stochastic optimal control of networked control systems with control packet dropouts

This paper considers the stochastic optimal control problem for networked control systems(NCSs)with control packet dropouts.The proportional plus up to the third-order derivative(PD3)compensation strategy is adopted to compensate for control packet dropouts at the actuator by using the past control packets stored in the buffer.Based on the strategy,a new NCS structure model with packet dropouts is provided,where the packet dropout is assumed to obey the Bernoulli random binary distribution.In terms of the given model,the stochastic optimal control law is proposed. Numerical examples illustrate the effectiveness of the results.     

Controller design for networked control system with data packet dropout and transmission delays

In this paper, the stabilization problem for a class of networked control systems （NCSs） with data packet dropouts and transmission time delays is considered, where the delays are time-varying and uncertain, the data packet dropout is modeled as a two-state Markov chain. To compensate the lost packet, a data packet dropout compensator is established. Thus a more realistic model for such NCSs is presented. Sufficient conditions for the stabilization of the new resulting system are derived in the form of linear matrix inequalities （LMIs）. Numerical example illustrates the solvability and effectiveness of the results.     

Controller design for networked control system with data packet dropout and transmission delays

In this paper, the stabilization problem for a class of networked control systems (NCSs) with data packet dropouts and transmission time delays is considered, where the delays are time-varying and uncertain, the data packet dropout is modeled as a two-state Markov chain. To compensate the lost packet, a data packet dropout compensator is established. Thus a more realistic model for such NCSs is presented. Sufficient conditions for the stabilization of the new resulting system are derived in the form of linear matrix inequalities (LMIs). Numerical example illustrates the solvability and effectiveness of the results.     

Finite-time boundedness and stabilisation of networked control systems with bounded packet dropout

In this paper, the finite-time boundedness and stabilisation problems of a class of networked control systems (NCSs) with bounded packet dropout are investigated. The main results provided in the paper are sufficient conditions for finite-time boundedness and stability via state feedback. An iterative approach is proposed to model NCSs with bounded packet dropout as jump linear systems (JLSs). Based on Lyapunov stability theory and JLSs theory, the sufficient conditions for finite-time boundedness and stabilisation of the underlying systems are derived via linear matrix inequalities (LMIs) formulation. Moreover, both sensor-to-controller and controller-to-actuator packet dropouts are considered simultaneously. Lastly, an illustrative example is given to demonstrate the effectiveness of the proposed results.     

网络控制系统的稳定性分析和研究

该文针对目前网络控制系统的研究现状,阐述了在网络控制系统的分析和设计中需要明确的几个基本问题。综述了具有时变传输周期、网络调度、数据丢包以及网络时滞时的网络控制系统的建模与各种控制策略问题。尤其是网络控制系统在这些情况下的稳定性研究问题,然后列举了一些具有代表性的网络控制系统稳定性分析的最新结果。在此基础上分析了网络控制系统稳定性分析研究中尚待解决的问题,以及新的研究方向。     

Output Feedback Stabilization of Networked Control Systems With Packet Dropouts

In this paper, we discuss the modeling and control of a class of networked control systems (NCSs) with packet dropouts. For the cases that there may be packet dropouts in both the backward and the forward channels in the communication network, and that the network-induced delays are shorter than one sampling period, the closed-loop NCS is modeled as a discrete-time switched system with four subsystems. By using the asynchronous dynamical systems approach and the average dwell-time method, sufficient conditions for the exponential stability of the closed-loop NCS are presented in terms of nonlinear matrix inequalities, and the relation between the packet dropout rate and the stability of the closed-loop NCS is explicitly established. A procedure involving an iterative algorithm is proposed to design the observer-based output feedback controllers. Lastly, an illustrative example is given to demonstrate the effectiveness of the proposed results.     

Compensation for control packet dropout in networked control systems

With the integration of communication networks and distributed control in modern manufacturing and process industries, networked control systems (NCSs) are becoming increasingly important due to its simplicity, scalability, flexibility, and cost effectiveness. However, there are still significant technical barriers that limit the applications of NCS technologies. Two challenges are network-induced time delay and data packet dropout. Applying a real-time queuing protocol that we developed recently, we are able to limit the sum of the network-induced communication delay and the control computation delay within a control period. This one-period delay is further guaranteed by well designed compensation for control packet dropout. Then, this paper proposes to compensate for the control packet dropout at the actuator using past control signals. Three model-free strategies for control packet dropout compensation, namely, PD (proportional plus derivative), PD2 (proportional plus up to the second-order derivative), and PD3 (proportional plus up to the third-order derivative) are developed. They are suitable for a large number of NCSs without the need to tune the compensator parameters. The proposed dropout compensation schemes are demonstrated through numerical examples.     

存在数据包丢失NCS系统的补偿估计器的建模与分析

对同时存在网络诱导时延及数据包丢失的一类网络控制系统进行了研究和分析。针对时延网络系统存在的数据包丢失,设计出包丢失估计补偿器,用补偿器的信息来更新控制器并建立系统模型,从而有效降低了时延和丢包对系统的影响,最终提高系统性能。与此同时,通过李亚普诺夫稳定性理论来对闭环系统进行了稳定性分析,并给出控制器的设计方法。最后,通过了实例仿真,证实了带补偿器和估计器的网络控制系统设计的有效性。     

有界丢包网络控制系统的稳定性与能稳性

主要讨论有界丢包网络控制系统的稳定性与能稳性. 基于迭代方法将有界丢包网络控制系统建模为一个跳变系统. 由于网络的复杂性, 跳变系统状态转移矩阵的部分元素无法获得, 因此, 我们考虑的这种情况更具有一般性. 并且本文考虑的丢包同时存在于前馈和反馈通道. 最后, 数值例子表明本文方法的有效性.     

STABILITY ANALYSIS OF NETWORKED SYSTEMS WITH PACKET DROPOUT AND TRANSMISSION DELAYS: DISCRETE‐TIME CASE

This paper analyzes the stability of networked control systems (NCSs) with data packet dropout and transmission delays induced by communication channels. Discrete‐time NCSs with data packet dropout and transmission delays are modeled as linear systems with time‐varying delays. Sufficient conditions for the stability of the NCSs are established in terms of linear matrix inequalities (LMIs) by using the Lyapunov function method. The case of NCSs with multiple‐packet transmission is also studied. A numerical example is presented to illustrate our proposed approach.     

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.     

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.     

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.     

时延丢包网络控制系统的分析与控制

针对网络控制系统中同时存在时延和丢包问题,基于零阶保持器的工作机制,将同时受时延和丢包影响的网络控制系统建模为输入带有时延的控制系统,根据李雅普诺夫稳定性理论和时滞系统理论得出控制系统的时滞相关稳定性条件,进一步基于锥补线性化的方法给出控制器的设计方法,有效解决了网络控制系统中同时存在时延和丢包的控制问题。仿真算例表明所提方法的有效性。     

Absolute stability of Lurie networked control systems

This paper is concerned with the absolute stability problem of networked control systems (NCSs) with the controlled plant being Lurie systems (Lurie NCSs), in which the network‐induced delays are assumed to be time‐varying and bounded. First, in consideration of both the time‐varying network‐induced delays and data packet dropouts, the Lurie NCSs can be modeled as a multiple‐delays Lurie system. Then, a delay‐dependent absolute stability condition is established by using the Lyapunov–Krasovskii method. Next, two approaches to controller design are proposed in the terms of simple algebra criteria, which are easily solved via the toolbox in Matlab. Furthermore, the main results can be extended to robust absolute stability of Lurie NCSs with the structured uncertainties, where robust absolute stability conditions and approaches to robust controller design are presented. Finally, two numerical examples are worked out to illustrate the feasibility and the effectiveness of the proposed method. Copyright © 2009 John Wiley & Sons, Ltd.     

基于主动变采样周期方法的网络控制系统的H∞控制器设计

This paper studies the problem of designing H∞ controllers for networked control systems (NCSs) with both network-induced time delay and packet dropout by using an active-varying sampling period method, where the sampling period switches in a finite set. A novel linear estimation-based method is proposed to compensate packet dropout, and H∞ controller design is also presented by using the multi-objective optimization methodology. The simulation results illustrate the effectiveness of the active-varying sampling period method and the linear estimation-based packet dropout compensation.     

Time delay and packet dropout compensation for networked control systems: a linear estimation method

This article studies the problem of H _∞ controller design for networked control systems (NCSs) with time delay and packet dropout. A linear estimation-based time delay and packet dropout compensation method is proposed. The delay switching-based method is presented to deal with the variation of time delay, and H _∞ controller design is presented for NCSs with packet dropout compensation by using linear matrix inequality (LMI)-based method. Then the combined delay switching and parameter uncertainty-based method is presented to model the variation of time delay, and H _∞ controller design is also presented. The simulation results illustrate the effectiveness of the newly proposed linear estimation-based time delay and packet dropout compensation.     

基于T-S模糊模型非线性网络控制系统改进H∞跟踪控制

研究一类非线性网络控制系统改进H∞跟踪控制问题, 该类网络控制系统中非线性被控对象和被跟踪对象分别采用Takagi-Sugeno(T-S)模糊模型和线性稳定参考模型描述. 首先通过综合考虑网络中的数据传输时滞和数据丢包影响, 采用输入时滞法和并行分布补偿技术, 建立基于零阶保持器刷新时刻的系统状态跟踪误差模型. 然后利用改进的自由权矩阵方法, 并结合Lyapunov直接法给出系统满足H∞跟踪性能的充分条件以及模糊控制器的设计方法. 最后仿真实例表明本文方法的有效性和相比已有方法的优越性.     

有时延和数据包丢失的网络控制系统控制器设计

在同时考虑网络诱导时延和数据包丢失的基础上,研究了动态输出反馈网络控制系统指数稳定性和控制器设计问题.基于一定的数据包丢失率和不大于一个采样周期的时延,将系统建模为结构事件率约束的异步动态系统.利用线性矩阵不等式方法推导出网络接通率约束的系统指数稳定的充要条件,给出了确保系统稳定的控制器设计方法.Matlab数值算例说明了研究结果是有效可行的.     

基于主动变采样周期方法的网络控制系统的H∞控制器设计

利用主动变采样周期方法, 本文研究了具有时延及丢包的网络控制系统的 H∞ 控制器设计问题, 其中采样周期在一个有限集合内切换. 提出了一个新的线性估计方法以补偿丢包的负面影响, 并利用多目标优化方法设计系统的 H∞ 控制器. 仿真结果表明了主动变采样周期方法及基于线性估计的丢包补偿方法的有效性.