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本文研究总比特率给定下随机向量参数分布式量化估计及其最优比特分配问题.与现有文献大都假定每个传感器的量化比特率给定而不是最优分配下研究随机性参数的分布式量化估计问题不同的是,本文将综合考虑最优量化器、最优估计器算法以及给定总比特率下的最优比特分配问题.针对向量状态标量观测模型,首先借助现有文献给出基于量化观测的最优估计器及其误差协方差阵形式表达,其次得到各传感器的渐近最优量化器实际为著名的Lloyd-max量化器,且各传感器的渐近最优量化级数与信噪比成正比,同时引入一种次优的求解非负整数比特率的方法.考虑到当传感器数目比较大时,初始的最优估计器算法运算量很大,设计了一种渐近等价的迭代量化估计器算法,其计算负担大大减轻,且对于存在延迟或丢包的网络环境亦适用,增强了算法的鲁棒性.仿真结果表明,本文提出的最优比特分配方案估计性能明显优于一般的均匀比特分配方案. 相似文献
2.
针对非线性网络化控制(NCS)系统中控制器参数存在摄动的问题,考虑传感器—控制器和控制器—执行器均存在随机丢包和量化误差,提出了一种加性非脆弱量化H∞控制器的设计方法.利用李亚普诺夫稳定性理论和线性矩阵不等式(LMI)方法,将该问题转化为线性矩阵不等式约束和线性目标函数的凸优化问题进行求解,给出了丢包下的非脆弱量化H∞控制器存在的充分条件.所设计的控制器在容许的参数摄动、丢包概率和量化密度条件下,不仅能保证闭环NCS的稳定性和性能要求,而且是非脆弱的.数值仿真验证了所提方法的有效性. 相似文献
3.
In this paper, we study the optimal regulation problem of networked control systems and propose a new performance index for a given discrete time-delay system. The regulation performance of the controlled plant is investigated by considering the effects of various constraints on the communication channel such as quantization, bandwidth, and packet dropouts using frequency domain methods and two-degree-of-freedom control techniques. The results show that the regulation performance is not only related to the location and direction of the non-minimum phase zeros and unstable poles of a given system but also related to the internal time delay of the controlled plant. Packet dropouts, quantization, and bandwidth limitations can also negatively affect the optimal performance. In addition, the trade-off of the input energy constraint can also make the optimal regulation performance suffer. Finally, the reliability of this innovative result is illustrated by some simulation examples. 相似文献
4.
Data Transmission Over Networks for Estimation and Control 总被引:1,自引:0,他引:1
Gupta V. Dana A.F. Hespanha J.P. Murray R.M. Hassibi B. 《Automatic Control, IEEE Transactions on》2009,54(8):1807-1819
We consider the problem of controlling a linear time invariant process when the controller is located at a location remote from where the sensor measurements are being generated. The communication from the sensor to the controller is supported by a communication network with arbitrary topology composed of analog erasure channels. Using a separation principle, we prove that the optimal linear-quadratic-Gaussian (LQG) controller consists of an LQ optimal regulator along with an estimator that estimates the state of the process across the communication network. We then determine the optimal information processing strategy that should be followed by each node in the network so that the estimator is able to compute the best possible estimate in the minimum mean squared error sense. The algorithm is optimal for any packet-dropping process and at every time step, even though it is recursive and hence requires a constant amount of memory, processing and transmission at every node in the network per time step. For the case when the packet drop processes are memoryless and independent across links, we analyze the stability properties and the performance of the closed loop system. The algorithm is an attempt to escape the viewpoint of treating a network of communication links as a single end-to-end link with the probability of successful transmission determined by some measure of the reliability of the network. 相似文献
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The problem of integrated design of controller and communication sequences is addressed for networked control systems with simultaneous consideration of medium access limitations and network‐induced delays, packet dropouts and measurement quantization. By exploiting a Lyapunov–Krasovskii functional and by making use of novel techniques for switching delay systems, it is shown that linear time invariant systems can be stabilized with delay‐dependent state feedback controllers and communication sequences satisfying appropriate delay‐dependent conditions in terms of linear matrix inequalities. Illustrative examples are provided to show the usefulness and advantage of the developed results. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
7.
Weijie Mao 《Asian journal of control》2013,15(5):1376-1384
This paper focuses on the problems of asymptotic stability and finite‐time stability (FTS) analysis, along with the state feedback controller design for networked control systems (NCSs) with consideration of both network‐induced delay and packet dropout. The closed‐loop NCS is modeled as a discrete‐time linear system with a time‐varying, bounded state delay. Sufficient conditions for the asymptotic stability and the FTS of the closed‐loop NCS are provided, respectively. Based on the stability analysis results, a mixed controller design method, which guarantees the asymptotic stability of the closed‐loop NCS in the usual case and the FTS of the closed‐loop NCS in the unusual case (that is, in some particular time intervals, large state delay occurs), is presented. A numerical example is provided to illustrate the effectiveness of the proposed mixed controller design method. 相似文献
8.
This paper is concerned with observer‐based H ∞ output tracking control for networked control systems. An observer‐based controller is implemented through a communication network to drive the output of a controlled plant to track the output of a reference model. The inputs of the controlled plant and the observer‐based tracking controller are updated in an asynchronous way because of the effects of network‐induced delays and packet dropouts in the controller‐to‐actuator channel. Taking the asynchronous characteristic into consideration, the resulting closed‐loop system is modeled as a system with two interval time‐varying delays. A Lyapunov–Krasovskii functional, which makes use of information about the lower and upper bounds of the interval time‐varying delays, is constructed to derive a delay‐dependent criterion such that the closed‐loop system has a desired H ∞ tracking performance. Notice that a separation principle cannot be used to design an observer gain and a control gain due to the asynchronous inputs of the plant and the controller. Instead, a novel design algorithm is proposed by applying a particle swarm optimization technique with the feasibility of the stability criterion to search for the minimum H ∞ tracking performance and the corresponding gains. The effectiveness of the proposed method is illustrated by an example. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
9.
Variable Gain Output Feedback Control of A Networked Temperature Control System Based on Online Delay Estimation
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In this paper, a gradient descent method based delay estimator is proposed for use with a variable gain control strategy for networked control systems. The delay estimator is developed in such a way that its boundedness is ensured. The performance of the estimator with variable gain controller is evaluated on a temperature control plant with network in the feedback loop. 相似文献
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This paper is concerned with the optimal linear estimation problem for discrete time-varying networked systems with communication constraints. The communication constraint considered is that only one network node is allowed to gain access to a shared communication channel, then the various network nodes of the networked systems are scheduled to transmit data according to a specified media access control protocol, and a remote estimator performs the estimation task with only partially available measurements. The channel accessing processes of those network nodes are modeled by Bernoulli processes, and optimal linear filters are designed by using the orthogonal projection principle and the innovation analysis approach. It is shown that the optimal estimation performances critically depend on the channel accessing probabilities of the network nodes and the packet loss probability, and the optimal filters can be obtained by solving recursive Lyapunov and Riccati equations. An illustrative example is finally given to show the effectiveness of the proposed filters. 相似文献
12.
Robust exponential stability of uncertain stochastic systems with probabilistic time‐varying delays
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This paper is concerned with the problem of delay‐distribution–dependent robust exponential stability for uncertain stochastic systems with probabilistic time‐varying delays. Firstly, inspired by a class of networked systems with quantization and packet losses, we study the stabilization problem for a class of network‐based uncertain stochastic systems with probabilistic time‐varying delays. Secondly, an equivalent model of the resulting closed‐loop network‐based uncertain stochastic system is constructed. Different from the previous works, the proposed equivalent system model enables the controller design of the network‐based uncertain stochastic systems to enjoy the advantage of probability distribution characteristic of packet losses. Thirdly, by applying the Lyapunov‐Krasovskii functional approach and the stochastic stability theory, delay‐distribution–dependent robust exponential mean‐square stability criteria are derived, and the sufficient conditions for the design of the delay‐distribution–dependent controller are then proposed to guarantee the stability of the resulting system. Finally, a case study is given to show the effectiveness of the results derived. Moreover, the allowable upper bound of consecutive packet losses will be larger in the case that the probability distribution characteristic of packet losses is taken into consideration. 相似文献
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In this paper, the past and current issues involved in the design of decentralized networked control systems are reviewed. The basic models of interconnected systems described as continuous-time linear time-invariant systems in the time domain serve as a framework for the inclusion of communication channels in the decentralized feedback loop. The I/O-oriented models and the interaction oriented models with disjoint subsystems and interactions are distinguished. The overview is focused on packet dropouts, transmission delays, and quantization effects which are included in the time-driven design of feedback loop components. Single- and multiple-packet transmissions are considered in this contents. The design of decentralized state feedback gain matrices with delayed feedback uses the methodology of sampled-data feedback design for continuous-time systems, while the decentralized H∞ quantizer design is based on the static output controller. The Liapunov stability approach results in computationally efficient decentralized control design strategies described by using linear matrix inequalities. 相似文献
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对于通讯信道具有丢包的网络化反馈控制系统, 运用乘性噪声模型来描述丢包这一信道不确定性, 并根据
网络化系统的结构特点提出了一种渐近跟踪控制器结构, 研究了该结构下系统的均方可镇定性以及均方最优渐近
跟踪与均方可镇定性的等价关系. 在此基础上, 运用随机均方最优控制理论给出了该系统均方最优渐近跟踪设计方
法, 该方法取决于广义代数黎卡提方程(MARE)的均方镇定解. 进一步, 本文提出了求解上述均方镇定解的新算法.
最后的仿真验证了对于信道具有丢包的网络化反馈系统最优渐近跟踪问题, 本文所提方法的有效性和可行性. 相似文献
15.
The research area of control over networks has attracted great interest in recent years. Inserted in this research area is
the study of control feedback limitations imposed by the presence of a communication channel. In this paper we analyze the
fundamental limitations in control feedback stabilizability imposed by a class of Signal-to-Noise Ratio (SNR) constrained
communication channels. We solve the SNR constrained control over network problem as a linear quadratic Gaussian (LQG) optimization
with loop transfer recovery (LTR). If the communication channel is located on the feedback path then the LTR is said to be
performed at the output. Vice versa, if the communication channel is on the control path, then the recovery is said to be
performed at the input. In the present paper we address both cases, namely the LQG optimization with LTR at the output and
the LQG optimization with LTR at the input to solve an LTI SNR constrained problem. We then explore the link between these
two solutions. 相似文献
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研究了具有时变时滞与多数据包丢失的网络控制系统(networked control systems,NCSs)的量化H∞控制问题.同时考虑传感器-控制器间的测量通道及控制器-执行器间的控制通道的多数据包丢失,并将其用满足Bernoulli分布的随机变量来表示.控制输入信号和测量输出信号分别在传感器和控制器两侧进行对数量化,量化误差描述为扇区有界不确定性.利用Lyapunov理论和线性矩阵不等式方法,得到了使得闭环NCSs满足一定H∞性能指标的均方意义下指数稳定充分条件,并给出了基于观测器的时滞相关控制器设计方法.最后,通过实例证明了该方法的有效性. 相似文献
17.
Quantized H_∞ fault-tolerant control for networked control systems (NCSs) with partial actuator fault with respect to actuators is concerned in this paper. Considering transmission delay, packet dropout and quantization, a synthesis model with partial actuator fault is established. The piecewise constant controller is adopted to model NCS with the transmission delay and packet dropout. Due to data transmitted in practical NCSs should be quantized before they are sent to the next network node, the logarithmic static and time-invariant quantizers at the sensor and controller sides are proposed in the paper. For the established model, an appropriate type of Lyapunov functions is provided to investigate the delay-dependent H_∞ control problem. According to an optimal problem, the controller that makes the system achieve the best performance is designed. Finally, an illustrative example is given to demonstrate the effectiveness of the proposed approach. 相似文献
18.
Fuwen Yang 《Asian journal of control》2013,15(5):1468-1476
The problem of quantized H∞ control for networked control systems (NCSs) subject to time‐varying delay and multiple packet dropouts is investigated in this paper. Both the control input and the measurement output signals are quantized before being transmitted and the quantized errors are described as sector bound uncertainties. The measurement channel and the control channel packet dropouts are considered simultaneously, and the stochastic variables satisfying Bernoulli random binary distribution are utilized to model the random multiple packet dropouts. Sufficient conditions for the existence of an observer‐based controller are established to ensure the exponential mean‐square stablility of the closed‐loop system and achieve the optimal H∞ disturbance attenuation level. By using a globally convergent algorithm involving convex optimization, the nonconvex feasibility can be solved successfully. Finally, a numerical example is given to illustrate the effectiveness and applicability of the proposed method. 相似文献
19.
Communication-Aware Formation Control of AUVs With Model Uncertainty and Fading Channel via Integral Reinforcement Learning
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Wenqiang Cao Jing Yan Xian Yang Xiaoyuan Luo Xinping Guan 《IEEE/CAA Journal of Automatica Sinica》2023,10(1):159-176
Most formation approaches of autonomous underwater vehicles (AUVs) focus on the control techniques, ignoring the influence of underwater channel. This paper is concerned with a communication-aware formation issue for AUVs, subject to model uncertainty and fading channel. An integral reinforcement learning (IRL) based estimator is designed to calculate the probabilistic channel parameters, wherein the multivariate probabilistic collocation method with orthogonal fractional factorial design (M-PCM-OFFD) is employed to evaluate the uncertain channel measurements. With the estimated signal-to-noise ratio (SNR), we employ the IRL and M-PCM-OFFD to develop a saturated formation controller for AUVs, dealing with uncertain dynamics and current parameters. For the proposed formation approach, an integrated optimization solution is presented to make a balance between formation stability and communication efficiency. Main innovations lie in three aspects: 1) Construct an integrated communication and control optimization framework; 2) Design an IRL-based channel prediction estimator; 3) Develop an IRL-based formation controller with M-PCM-OFFD. Finally, simulation results show that the formation approach can avoid local optimum estimation, improve the channel efficiency, and relax the dependence of AUV model parameters. 相似文献
20.
王春平 《计算机测量与控制》2020,28(12):186-190
网络控制系统是通过实时网络来形成闭环反馈的控制系统。网络的介入会带来许多不确定因素,包括网络诱导时延和数据包丢失以及量化误差,它们会影响系统的稳定性,严重时甚至会导致系统失稳。本文针对短时延网络控制系统,考虑传感器-控制器和控制器-执行器两个通道都存在数据包丢失,在传感器到控制器端设立量化器,将系统建模为一个异步动态系统,利用异步动态系统指数稳定性理论、线性矩阵不等式工具分析了闭环系统稳定性,并基于MATLAB软件的线性矩阵不等式(LMI)工具箱实验仿真进行有效性验证,结果证明了方案的可行性,最后给出控制器参数的设计方法。 相似文献