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Automatic Control, IEEE Transactions on

Issue 3 • Date March 2009

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Displaying Results 1 - 25 of 37
  • Table of contents

    Publication Year: 2009 , Page(s): C1 - C4
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    Freely Available from IEEE
  • IEEE Transactions on Automatic Control publication information

    Publication Year: 2009 , Page(s): C2
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    Freely Available from IEEE
  • Editorial A Beautiful Time

    Publication Year: 2009 , Page(s): 421
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  • Scanning the issue

    Publication Year: 2009 , Page(s): 422 - 423
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    Freely Available from IEEE
  • Detectability and Stabilizability of Discrete-Time Switched Linear Systems

    Publication Year: 2009 , Page(s): 424 - 437
    Cited by:  Papers (15)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (513 KB) |  | HTML iconHTML  

    For discrete-time switched linear systems under nondeterministic autonomous switching, the existence of causal finite-path-dependent stabilizing output injection and state feedback laws are characterized by increasing unions of linear matrix inequality conditions. These convex characterizations lead to the notions of causal finite-path-dependent detectability and stabilizability, which in turn yield a separation result for dynamic output feedback stabilization. By generalizing the standard duality concept to switched systems under arbitrary switching path constraints, we relate these notions to direct extensions of time-varying detectability and stabilizability requirements. View full abstract»

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  • On Feedback Stabilizability of Linear Systems With State and Input Delays in Banach Spaces

    Publication Year: 2009 , Page(s): 438 - 451
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (472 KB) |  | HTML iconHTML  

    The feedback stabilizability of a general class of well-posed linear systems with state and input delays in Banach spaces is studied in this paper. Using the properties of infinite dimensional linear systems, a necessary condition for the feedback stabilizability of delay systems is presented, which extends the well-known results for finite dimensional systems to infinite dimensional ones. This condition becomes sufficient as well if the semigroup of the delay-free system is immediately compact and the control space is finite dimensional. Moreover, under the condition that the Banach space is reflexive, a rank condition in terms of eigenvectors and control operators is proposed. When the delay-free state space and control space are all finite dimensional, a very compact rank condition is obtained. Finally, the abstract results are illustrated with examples. View full abstract»

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  • Self-Triggered Feedback Control Systems With Finite-Gain {cal L}_{2} Stability

    Publication Year: 2009 , Page(s): 452 - 467
    Cited by:  Papers (92)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1109 KB) |  | HTML iconHTML  

    This paper examines a class of real-time control systems in which each control task triggers its next release based on the value of the last sampled state. Prior work used simulations to demonstrate that self-triggered control systems can be remarkably robust to task delay. This paper derives bounds on a task's sampling period and deadline to quantify how robust the control system's performance will be to variations in these parameters. In particular we establish inequality constraints on a control task's period and deadline whose satisfaction ensures that the closed-loop system's induced L 2 gain lies below a specified performance threshold. The results apply to linear time-invariant systems driven by external disturbances whose magnitude is bounded by a linear function of the system state's norm. The plant is regulated by a full-information H infin controller. These results can serve as the basis for the design of soft real-time systems that guarantee closed-loop control system performance at levels traditionally seen in hard real-time systems. View full abstract»

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  • On Solvability of a Decentralized Supervisory Control Problem With Communication

    Publication Year: 2009 , Page(s): 468 - 480
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (432 KB) |  | HTML iconHTML  

    We study a decentralized control problem of discrete event systems with communication. We first give a general automata-theoretic formalism that enables us to handle various types of communication, including delay. The decentralized control problem is shown to be undecidable under this formalism. Next we propose a semi-decision procedure for computing finite-state controllers to achieve a given specification in the sense of bisimilarity between the controlled system and a given specification. Using this procedure, we prove decidability of the problem for two special cases, one is the case in which the communication behavior is given as k -bounded-delay communication, and the other is the case in which any cycle in the state transition diagram of the system contains an event observable by all controllers. We also show a method for optimizing controllers based on a graph problem. View full abstract»

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  • Markov Chain Monte Carlo Data Association for Multi-Target Tracking

    Publication Year: 2009 , Page(s): 481 - 497
    Cited by:  Papers (29)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1016 KB) |  | HTML iconHTML  

    This paper presents Markov chain Monte Carlo data association (MCMCDA) for solving data association problems arising in multitarget tracking in a cluttered environment. When the number of targets is fixed, the single-scan version of MCMCDA approximates joint probabilistic data association (JPDA). Although the exact computation of association probabilities in JPDA is NP-hard, we prove that the single-scan MCMCDA algorithm provides a fully polynomial randomized approximation scheme for JPDA. For general multitarget tracking problems, in which unknown numbers of targets appear and disappear at random times, we present a multi-scan MCMCDA algorithm that approximates the optimal Bayesian filter. We also present extensive simulation studies supporting theoretical results in this paper. Our simulation results also show that MCMCDA outperforms multiple hypothesis tracking (MHT) by a significant margin in terms of accuracy and efficiency under extreme conditions, such as a large number of targets in a dense environment, low detection probabilities, and high false alarm rates. View full abstract»

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  • Cross-Term Forwarding for Systems With Time Delay

    Publication Year: 2009 , Page(s): 498 - 511
    Cited by:  Papers (17)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (600 KB) |  | HTML iconHTML  

    This paper presents a Lyapunov-based control design method for nonlinear systems with time delay. The key step is construction of a composite Lyapunov functionalV for a stable cascade. This functional consists of Lyapunov functionals for the subsystems and a cross-term defined by an infinite integral. The ldquoL g V-typerdquo control law is then employed to achieve global asymptotic stability. The design procedure can be applied recursively to stabilize complex feedforward structures. When applied to a linear cascade, it gives a formula for the control law even if some parts of the system can only be stabilized through channels with multiple non-commensurate or distributed delays. View full abstract»

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  • Energy-Efficient Decentralized Cooperative Routing in Wireless Networks

    Publication Year: 2009 , Page(s): 512 - 527
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (793 KB) |  | HTML iconHTML  

    Wireless adhoc networks transmit information from a source to a destination via multiple hops in order to save energy and, thus, increase the lifetime of battery-operated nodes. The energy savings can be especially significant in cooperative transmission schemes, where several nodes cooperate during one hop to forward the information to the next node along a route to the destination. Finding the best multi-hop transmission policy in such a network which determines nodes that are involved in each hop, is a very important problem, but also a very difficult one especially when the physical wireless channel behavior is to be accounted for and exploited. We model the above optimization problem for randomly fading channels as a decentralized control problem - the channel observations available at each node define the information structure, while the control policy is defined by the power and phase of the signal transmitted by each node. In particular, we consider the problem of computing an energy-optimal cooperative transmission scheme in a wireless network for two different channel fading models: (i) slow fading channels, where the channel gains of the links remain the same for a large number of transmissions, and (ii) fast fading channels, where the channel gains of the links change quickly from one transmission to another. For slow fading, we consider a factored class of policies (corresponding to local cooperation between nodes), and show that the computation of an optimal policy in this class is equivalent to a shortest path computation on an induced graph, whose edge costs can be computed in a decentralized manner using only locally available channel state information (CSI). For fast fading, both CSI acquisition and data transmission consume energy. Hence, we need to jointly optimize over both these; we cast this optimization problem as a large stochastic optimization problem. We then jointly optimize over a set of CSI functions of the local channel states, and a c- - orresponding factored class of control policies corresponding to local cooperation between nodes with a local outage constraint. The resulting optimal scheme in this class can again be computed efficiently in a decentralized manner. We demonstrate significant energy savings for both slow and fast fading channels through numerical simulations of randomly distributed networks. View full abstract»

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  • Ensemble Control of Bloch Equations

    Publication Year: 2009 , Page(s): 528 - 536
    Cited by:  Papers (38)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (377 KB) |  | HTML iconHTML  

    In this article, we study a class of control problems which involves controlling a continuum of dynamical systems with different values of parameters characterizing the system dynamics by using the same control signal. We call such problems control of ensembles. The motivation for looking into these problems comes from the manipulation of an ensemble of nuclear spins in nuclear magnetic resonance (NMR) spectroscopy and imaging (MRI) with dispersions in natural frequencies and the strengths of the applied radio frequency (rf) field. From the standpoint of mathematical control theory, the challenge is to simultaneously steer a continuum of systems between points of interest with the same control input. This raises some new and unexplored questions about controllability of such systems. We show that controllability of an ensemble can be understood by the study of the algebra of polynomials defined by the noncommuting vector fields that govern the system dynamics. A systematic study of these systems has immediate applications to broad areas of control of ensembles of quantum systems as arising in coherent spectroscopy and quantum information processing. The new mathematical structures appearing in such problems are excellent motivation for new developments in control theory. View full abstract»

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  • Compensation of Complex Hysteresis and Creep Effects in Piezoelectrically Actuated Systems —A New Preisach Modeling Approach

    Publication Year: 2009 , Page(s): 537 - 550
    Cited by:  Papers (25)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (628 KB) |  | HTML iconHTML  

    Undesired complex hysteretic nonlinearities and complex log(t)-type creep dynamics with asymmetrical branching characteristics are present to varying degrees in virtually all smart-material based sensors and actuators provided that they are driven with sufficiently high amplitudes. In motion and active vibration control applications, for example, these nonlinearities can excite unwanted dynamics which leads in the best case to reduced closed-loop system performance and in the worst case to unstable closed-loop system operation. From the practical point of view it is extremely useful to cancel these types of nonlinearities by a feedforward compensation strategy. Therefore, the present article describes a new compensator for these types of actuator nonlinearities with large creep processes based on the so-called Preisach approach. It discusses a rigorous existence, uniqueness and stability proof for the compensator. Moreover, it deduces an algorithm for the calculation of the compensator in real-time applications and presents some experimental results which document the applicability of the method for practical applications. View full abstract»

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  • An Improved Link Model for Window Flow Control and Its Application to FAST TCP

    Publication Year: 2009 , Page(s): 551 - 564
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1344 KB) |  | HTML iconHTML  

    This paper presents a link model which captures the queue dynamics in response to a change in a transmission control protocol (TCP) source's congestion window. By considering both self-clocking and the link integrator effect, the model generalizes existing models and is shown to be more accurate by both open loop and closed loop packet level simulations. It reduces to the known static link model when flows' round trip delays are identical, and approximates the standard integrator link model when there is significant cross traffic. We apply this model to the stability analysis of fast active queue management scalable TCP (FAST TCP) including its filter dynamics. Under this model, the FAST control law is linearly stable for a single bottleneck link with an arbitrary distribution of round trip delays. This result resolves the notable discrepancy between empirical observations and previous theoretical predictions. The analysis highlights the critical role of self-clocking in TCP stability, and the proof technique is new and less conservative than existing ones. View full abstract»

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  • Intelligent Packet Dropping for Optimal Energy-Delay Tradeoffs in Wireless Downlinks

    Publication Year: 2009 , Page(s): 565 - 579
    Cited by:  Papers (21)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (406 KB) |  | HTML iconHTML  

    We explore the advantages of intelligently dropping a small fraction of packets that arrive for transmission over a time varying wireless downlink. Without packet dropping, the optimal energy-delay tradeoff conforms to a square root tradeoff law, as shown by Berry and Gallager (2002). We show that intelligently dropping any non-zero fraction of the input rate dramatically changes this relation from a square root tradeoff law to a logarithmic tradeoff law. Further, we demonstrate an innovative algorithm for achieving this logarithmic tradeoff without requiring a-priori knowledge of arrival rates or channel probabilities. The algorithm can be implemented in real time and easily extends to yield similar performance for multi-user systems. View full abstract»

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  • Extremum Seeking With Stochastic Perturbations

    Publication Year: 2009 , Page(s): 580 - 585
    Cited by:  Papers (21)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (283 KB) |  | HTML iconHTML  

    Extremum seeking (ES) using deterministic periodic perturbations has been an effective method for non-model based real time optimization when only limited plant knowledge is available. However, periodicity can naturally lead to predictability which is undesirable in some tracking applications and unrepresentative of biological optimization processes such as bacterial chemotaxis. With this in mind, it is useful to investigate employing stochastic perturbations in the context of a typical ES architecture, and to compare the approach with existing stochastic optimization techniques. In this work, we show that convergence towards the extremum of a static map can be guaranteed with a stochastic ES algorithm, and quantify the behavior of a system with Gaussian-distributed perturbations at the extremum in terms of the ES constants and map parameters. We then examine the closed loop system when actuator dynamics are included, as the separation of time scales between the perturbation signal and plant dynamics recommended in periodic ES schemes cannot be guaranteed with stochastic perturbations. Consequently, we investigate how actuator dynamics influence the allowable range of ES parameters and necessitate changes in the closed loop structure. Finally simulation results are presented to demonstrate convergence and to validate predicted behavior about the extremum. For the sake of analogy with the classical methods of stochastic approximation, stochastic ES in this technical note is pursued in discrete time. View full abstract»

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  • Controllability of Spacecraft Attitude Using Control Moment Gyroscopes

    Publication Year: 2009 , Page(s): 585 - 590
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (238 KB) |  | HTML iconHTML  

    This technical note describes an application of nonlinear controllability theory to the problem of spacecraft attitude control using control moment gyroscopes (CMGs). Nonlinear controllability theory is used to show that a spacecraft carrying one or more CMGs is controllable on every angular momentum level set in spite of the presence of singular CMG configurations, that is, given any two states having the same angular momentum, any one of them can be reached from the other using suitably chosen motions of the CMG gimbals. This result is used to obtain sufficient conditions on the momentum volume of the CMG array that guarantee the existence of gimbal motions which steer the spacecraft to a desired spin state or rest attitude. View full abstract»

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  • Sensitivity Minimization by Strongly Stabilizing Controllers for a Class of Unstable Time-Delay Systems

    Publication Year: 2009 , Page(s): 590 - 595
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (537 KB) |  | HTML iconHTML  

    Weighted sensitivity minimization is studied within the framework of strongly stabilizing (stable) Hinfin controller design for a class of infinite dimensional systems. This problem has been solved by Ganesh and Pearson, for finite dimensional plants using Nevanlinna-Pick interpolation. We extend their technique to a class of unstable time delay systems. Moreover, we illustrate suboptimal solutions, and their robust implementation. View full abstract»

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  • Recursive Noise Adaptive Kalman Filtering by Variational Bayesian Approximations

    Publication Year: 2009 , Page(s): 596 - 600
    Cited by:  Papers (24)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (352 KB) |  | HTML iconHTML  

    This article considers the application of variational Bayesian methods to joint recursive estimation of the dynamic state and the time-varying measurement noise parameters in linear state space models. The proposed adaptive Kalman filtering method is based on forming a separable variational approximation to the joint posterior distribution of states and noise parameters on each time step separately. The result is a recursive algorithm, where on each step the state is estimated with Kalman filter and the sufficient statistics of the noise variances are estimated with a fixed-point iteration. The performance of the algorithm is demonstrated with simulated data. View full abstract»

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  • Attitude Tracking and Disturbance Rejection of Rigid Spacecraft by Adaptive Control

    Publication Year: 2009 , Page(s): 600 - 605
    Cited by:  Papers (28)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (310 KB) |  | HTML iconHTML  

    In this technical note, we deal with the attitude tracking and disturbance rejection problem of spacecraft for a class of persistent disturbances with unbounded energy which include the sinusoidal disturbance as a special case. The approach involves the integration of techniques from robust control, adaptive control, and robust output regulation theory. View full abstract»

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  • Simultaneous H^{\infty } Control for Nonlinear Systems

    Publication Year: 2009 , Page(s): 606 - 610
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (223 KB) |  | HTML iconHTML  

    This note develops a novel method for designing simultaneous H infin state feedback controllers for a collection of single-input nonlinear systems. Based on the Kalman-Yakubovich-Popov Lemma, necessary and sufficient conditions for the existence of simultaneous H infin controllers are derived by the control storage function approach. A universal formula for constructing continuous, time-invariant, simultaneous H infin state feedback controllers is presented. View full abstract»

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  • A Necessary and Sufficient Frequency Domain Criterion for the Passivity of SISO Sampled-Data Systems

    Publication Year: 2009 , Page(s): 611 - 614
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (157 KB) |  | HTML iconHTML  

    We present a frequency domain solution to the sampled-data passivity problem. Our analysis is exact in the sense that we take into account the intersample behavior of the system. We use frequency response (FR) operators to first obtain necessary conditions on the sampling rate T and the relative degree of the open-loop transfer function G 11 for achieving a passive continuous-time closed-loop system. Then, assuming passivity of G 11 and closed-loop stability, we derive a necessary and sufficient condition for discrete-time controllers that render a passive closed-loop system. We apply the obtained results to the problem of stability of haptic systems. View full abstract»

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  • Flatness of Switched Linear Discrete-Time Systems

    Publication Year: 2009 , Page(s): 615 - 619
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (201 KB) |  | HTML iconHTML  

    This note is devoted to flatness for switched linear discrete-time systems. For this class of hybrid systems, algebraic conditions are derived to check whether a given output is flat. Then, a feedforward flatness-based control strategy for trajectory tracking is proposed. View full abstract»

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  • Explicit Computation of the Sampling Period in Emulation of Controllers for Nonlinear Sampled-Data Systems

    Publication Year: 2009 , Page(s): 619 - 624
    Cited by:  Papers (25)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (245 KB) |  | HTML iconHTML  

    The purpose of this note is to apply recent results on stabilization of networked control systems to obtain an explicit formula for the maximum allowable sampling period (MASP) that guarantees stability of a nonlinear sampled-data system with an emulated controller. Such formulas are of great value to control practitioners. View full abstract»

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  • Non-Fragile Exponential Stability Assignment of Discrete-Time Linear Systems With Missing Data in Actuators

    Publication Year: 2009 , Page(s): 625 - 630
    Cited by:  Papers (18)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (366 KB) |  | HTML iconHTML  

    This technical note is concerned with the non-fragile exponential stabilization for a class of discrete-time linear systems with missing data in actuators. The process of missing data is modeled by a discrete-time Markov chain with two state components. When no uncertainty exists in the controllers, a necessary and sufficient condition, which not only guarantees the exponential stability but also gives a lower bound on the decay rate, is established in terms of linear matrix inequalities (LMIs). Based on this condition, an LMI-based approach is provided to design a non-fragile state-feedback controller such that the closed-loop system is exponentially stable with a prescribed lower bound on the decay rate for the known missing data process and all admissible uncertainties in controllers. A numerical example is provided to show the effectiveness of the theoretical results. View full abstract»

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Aims & Scope

In the IEEE Transactions on Automatic Control, the IEEE Control Systems Society publishes high-quality papers on the theory, design, and applications of control engineering.  Two types of contributions are regularly considered

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
P. J. Antsaklis
Dept. Electrical Engineering
University of Notre Dame