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Automatic Control, IEEE Transactions on

Issue 4 • Date April 2007

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Displaying Results 1 - 25 of 30
  • Table of contents

    Page(s): C1 - C4
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  • IEEE Transactions on Automatic Control publication information

    Page(s): C2
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  • Scannings for April 2007

    Page(s): 585
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  • A Negative Bendixson-Like Criterion for a Class of Hybrid Systems

    Page(s): 586 - 595
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (595 KB) |  | HTML iconHTML  

    A condition which ensures the absence of periodic orbits for nonsmooth dynamical systems is presented. The condition is a higher dimensional generalization of Bendixson's criterion applicable to differential inclusions that are useful in the description of hybrid systems. The main argument is based on contraction analysis of the d-measured volume along the system trajectories. A connection to methods for estimating the Hausdorff dimension is emphasized. For a class of hybrid systems described by a linear system with relay feedback the conditions are presented in the form of linear matrix inequalities. A simple but illustrative example is analyzed View full abstract»

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  • Multistability in Systems With Counter-Clockwise Input–Output Dynamics

    Page(s): 596 - 609
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (446 KB) |  | HTML iconHTML  

    The notion of counterclockwise (CCW) input-output dynamics is extended and used for the global analysis of multistability in positive feedback interconnections. A library of examples is provided to illustrate the usefulness of this concept and help recognizing CCW dynamics in specific applications, especially those arising in systems biology View full abstract»

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  • Direct Adaptive Dynamic Compensation for Minimum Phase Systems With Unknown Relative Degree

    Page(s): 610 - 621
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (722 KB) |  | HTML iconHTML  

    We consider parameter-monotonic direct adaptive control for single-input-single-output minimum-phase linear time-invariant systems with knowledge of the sign of the high-frequency gain (first nonzero Markov parameter) and an upper bound on the magnitude of the high-frequency gain. The first part of the paper is devoted to fixed-gain analysis of single-parameter high-gain-stabilizing controllers. Two novel fixed-gain dynamic compensators are presented for stabilizing minimum-phase systems. One compensator stabilizes systems with arbitrary-but-known relative degree, while the other utilizes a Fibonacci series construction to stabilize systems with unknown-but-bounded relative degree. Next, we provide a general treatment of parameter-monotonic adaptive control, including a result that guarantees state convergence to zero. This result is then combined with the high-gain-stabilizing controllers to yield parameter-monotonic direct adaptive dynamic compensation for minimum-phase systems with either arbitrary-but-known or unknown-but-bounded relative degree View full abstract»

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  • State-Space Reconstruction and Spatio-Temporal Prediction of Lattice Dynamical Systems

    Page(s): 622 - 632
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1371 KB) |  | HTML iconHTML  

    This paper addresses the problems of state space reconstruction and spatio-temporal prediction for lattice dynamical systems. It is shown that the state space of any finite lattice dynamical system can be embedded into a reconstruction space for almost every, in the sense of prevalence, smooth measurement mapping as long as the dimension of the reconstruction space is larger than twice the size of the lattice. Based on this result, an input-output spatio-temporal dynamical relation for each site within the lattice is derived and used for spatio-temporal prediction of the system. In the case of infinite lattice dynamical systems, an approach based on constructing local lattice dynamical systems is proposed. It is shown that the finite dimensional results can be directly applied to the local modelling and spatio-temporal prediction for infinite lattice dynamical systems. Two numerical examples are provided to demonstrate the proposed theory and approach View full abstract»

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  • Switching Stabilizability for Continuous-Time Uncertain Switched Linear Systems

    Page(s): 633 - 646
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (834 KB) |  | HTML iconHTML  

    This paper investigates the switching stabilizability problem for a class of continuous-time switched linear systems with time-variant parametric uncertainties. First, a necessary and sufficient condition for the asymptotic stabilizability of such uncertain switched linear system is derived, under the assumption that the closed-loop switched system does not generate sliding motions. Then, an additional condition is introduced to exclude the possibility of unstable sliding motions. Finally, a necessary and sufficient for the asymptotic stabilizability of such continuous-time uncertain switched linear systems is presented. This result improves upon conditions found in the literature which are either sufficient only or necessary only View full abstract»

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  • Stochastic Uncertain Systems Subject to Relative Entropy Constraints: Induced Norms and Monotonicity Properties of Minimax Games

    Page(s): 647 - 663
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (517 KB) |  | HTML iconHTML  

    Entropy and relative entropy are fundamental concepts on which information theory is founded on, and in general, telecommunication systems design. On the other hand, dissipation inequalities, minimax strategies, and induced norms are the basic concepts on which robustness of uncertain control and estimation of systems are founded on. In this paper, the precise relation between these notions is investigated. In particular, it will be shown that the higher the dissipation the higher the entropy of the system, which has implications in computing the induced norm associated with robustness. These connections are obtained by considering stochastic optimal uncertain control systems, in which uncertainty is described by a relative entropy constraint between the nominal and uncertain measures, while the pay-off is a linear functional of the uncertain measure. This is a minimax game, in which the controller measure seeks to minimize the pay-off, while the disturbance measure aims at maximizing the pay-off. Salient properties of the minimax solution are derived, including a characterization of the optimal sensitivity reduction, computation of the induced norm, monotonicity properties of minimax solution, and relations between dissipation and relative entropy of the system. The theory is developed in an abstract setting and then applied to nonlinear partially observable continuous-time uncertain controlled systems, in which the nominal and uncertain systems are described by conditional distributions. In addition, existence of the optimal control policy among the class of policies known as wide-sense control laws is shown, and an explicit formulae for the worst case conditional measure is derived. The results are applied to linear-quadratic-Gaussian problems View full abstract»

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  • SDU: A Semidefinite Programming-Based Underestimation Method for Stochastic Global Optimization in Protein Docking

    Page(s): 664 - 676
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1200 KB) |  | HTML iconHTML  

    This paper introduces a new stochastic global optimization method targeting protein-protein docking problems, an important class of problems in computational structural biology. The method is based on finding general convex quadratic underestimators to the binding energy function that is funnel-like. Finding the optimum underestimator requires solving a semidefinite programming problem, hence the name semidefinite programming-based underestimation (SDU). The underestimator is used to bias sampling in the search region. It is established that under appropriate conditions SDU locates the global energy minimum with probability approaching one as the sample size grows. A detailed comparison of SDU with a related method of convex global underestimator (CGU), and computational results for protein-protein docking problems are provided View full abstract»

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  • Partially Observable Markov Decision Processes With Reward Information: Basic Ideas and Models

    Page(s): 677 - 681
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (209 KB) |  | HTML iconHTML  

    In a partially observable Markov decision process (POMDP), if the reward can be observed at each step, then the observed reward history contains information on the unknown state. This information, in addition to the information contained in the observation history, can be used to update the state probability distribution. The policy thus obtained is called a reward-information policy (RI-policy); an optimal RI-policy performs no worse than any normal optimal policy depending only on the observation history. The above observation leads to four different problem-formulations for POMDPs depending on whether the reward function is known and whether the reward at each step is observable. This exploratory work may attract attention to these interesting problems View full abstract»

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  • Distributed Geodesic Control Laws for Flocking of Nonholonomic Agents

    Page(s): 681 - 686
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (632 KB) |  | HTML iconHTML  

    We study the problem of flocking and velocity alignment in a group of kinematic nonholonomic agents in 2 and 3 dimensions. By analyzing the velocity vectors of agents on a circle (for planar motion) or sphere (for 3-D motion), we develop a geodesic control law that minimizes a misalignment potential and results in velocity alignment and flocking. The proposed control laws are distributed and will provably result in flocking when the underlying proximity graph which represents the neighborhood relation among agents is connected. We further show that flocking is possible even when the topology of the proximity graph changes over time, so long as a weaker notion of joint connectivity is preserved View full abstract»

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  • Fundamental Constraints on Uncertainty Evolution in Hamiltonian Systems

    Page(s): 686 - 691
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (281 KB) |  | HTML iconHTML  

    A realization of Gromov's nonsqueezing theorem and its applications to uncertainty analysis in Hamiltonian systems are studied in this note. Gromov's nonsqueezing theorem describes a fundamental property of symplectic manifolds, however, this theorem is usually started in terms of topology and its physical meaning is vague. In this note we introduce a physical interpretation of the linear symplectic width, which is the lower bound in the nonsqueezing theorem, in terms of the eigenstructure of a positive-definite, symmetric matrix. Since uncertainty is often represented in terms of a positive definite, symmetric matrix in control theory, our study can be applied to uncertainty analysis by applying the nonsqueezing theorem to the uncertainty ellipsoid. We find a fundamental inequality for the evolving uncertainty in a linear dynamical system and provide some numerical examples View full abstract»

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  • An Invariance Principle for Nonlinear Discrete Autonomous Dynamical Systems

    Page(s): 692 - 697
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (377 KB) |  | HTML iconHTML  

    This note proposes an extension of LaSalle's invariance principle for nonlinear discrete autonomous dynamical systems. The invariance principle is extended to allow the first difference of the auxiliar scalar function (usually a Lyapunov function) to be positive in some bounded regions. Moreover, a uniform version is proposed to deal with nonlinear discrete dynamical systems that vary with parameters. Both extensions have the original invariance principle as a particular case. As a consequence, a larger class of systems can be treated with this new theory. The extensions are very useful to obtain attractor estimates as well as their corresponding stability regions. The uniform version, in particular, is useful to obtain estimates that are uniform regarding parameters View full abstract»

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  • Computing  {{\bf L}_{2}} -Gain of Finite-Horizon Systems With Boundary Conditions

    Page(s): 697 - 702
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (290 KB) |  | HTML iconHTML  

    A bisection algorithm is developed for computing the L2-gain of a finite-horizon system with boundary conditions. Upper and lower bounds of the gain are also derived for the initial step of the algorithm View full abstract»

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  • Adaptive Regulator for Hammerstein and Wiener Systems With Noisy Observations

    Page(s): 703 - 709
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (378 KB) |  | HTML iconHTML  

    For Hammerstein and Wiener systems observed with additive noises the adaptive regulation control is produced by a truncated stochastic approximation (SA) algorithm with truncation regions expanding with a prescribed rate. It is proved that the stochastic adaptive control given in this note is optimal in the sense that it minimizes the long run average of regulation errors a.s View full abstract»

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  • On the Discrete-Time Integral Sliding-Mode Control

    Page(s): 709 - 715
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (561 KB) |  | HTML iconHTML  

    A new discrete-time integral sliding-mode control (DISMC) scheme is proposed for sampled-data systems. The new control scheme is characterized by a discrete-time integral sliding manifold which inherits the desired properties of the continuous-time integral sliding manifold, such as full order sliding manifold with pole assignment, and elimination of the reaching phase. In particular, comparing with existing discrete-time sliding-mode control, the new scheme is able to achieve more precise tracking performance. It will be shown in this work that, the new control scheme achieves O(T2) steady-state error for state regulation with the widely adopted delay-based disturbance estimation. Another desirable feature is, the proposed DISMC prevents the generation of overlarge control actions due to deadbeat response, which is usually inevitable due to the existence of poles at the origin for a reduced order sliding manifold designed for sampled-data systems. Both the theoretical analysis and illustrative example demonstrate the validity of the proposed scheme View full abstract»

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  • Certainty-Equivalence Feedback Design With Polynomial-Type Feedbacks Which Guarantee ISS

    Page(s): 716 - 720
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (222 KB) |  | HTML iconHTML  

    The purpose of this note is to establish a certainty-equivalence feedback design for inverse optimally controlled affine systems. In particular, it is shown that a class of polynomial-type state feedbacks in conjunction with a globally asymptotically convergent observer leads to a globally asymptotically stable closed-loop. A key step in the proposed certainty-equivalence feedback design procedure is the identification of a new class of polynomial-type inverse optimal feedbacks which guarantees input-to-state stability (ISS) with respect to measurement errors. As a consequence, the proposed certainty-equivalence feedback design has the important feature that the state feedback is allowed to contain polynomial nonlinearities of arbitrarily high degree in the unmeasured states. This feature is illustrated on an example View full abstract»

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  • Stability Criteria of Linear Neutral Systems With Multiple Delays

    Page(s): 720 - 724
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (235 KB) |  | HTML iconHTML  

    In the present note, stability of linear neutral systems with multiple delays is investigated. By principle of the argument, stability criteria are derived which are necessary and sufficient for asymptotic stability of the neutral systems. The stability criteria need only to evaluate the characteristic function and the argument on the boundary of a certain rectangular region. Several numerical examples are given to illustrate the results View full abstract»

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  • Order Bound for the Realization of a Combination of Positive Filters

    Page(s): 724 - 729
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (270 KB) |  | HTML iconHTML  

    In a problem on the realization of digital filters, initiated by Gersho and Gopinath, we extend and complete a remarkable result of Benvenuti, Farina and Anderson on decomposing the transfer function t(z) of an arbitrary linear, asymptotically stable, discrete, time-invariant single-input-single-output system as a difference t(z)=t1(z)-t2(z) of two positive, asymptotically stable linear systems. We give an easy-to-compute algorithm to handle the general problem, in particular, also the case of transfer functions t(z) with multiple poles, which was left open in a previous paper. One of the appearing positive, asymptotically stable systems is always one-dimensional, while the other has dimension depending on the order and, in the case of nonreal poles, also on the location of the poles of t(z). The appearing dimension is seen to be minimal in some cases and it can always be calculated before carrying out the realization View full abstract»

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  • Detectability and Output Feedback Stabilizability of Nonlinear Networked Control Systems

    Page(s): 730 - 735
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (328 KB) |  | HTML iconHTML  

    This note addresses problems of detectability and output feedback stabilizability of nonlinear systems with globally Lipschitz nonlinearities via limited capacity digital communication channels. The main results are given in terms of Riccati algebraic inequalities. A simulation result on the control of a flexible joint robotic system is also presented View full abstract»

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  • LMI-Based Sliding Surface Design for Integral Sliding Mode Control of Mismatched Uncertain Systems

    Page(s): 736 - 742
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (330 KB) |  | HTML iconHTML  

    We propose a linear matrix inequality (LMI)-based sliding surface design method for integral sliding-mode control of mismatched uncertain systems. The uncertain system under consideration may have mismatched norm bounded uncertainties in the state matrix as well as the input matrix. We give a sufficient condition for the existence of a sliding surface guaranteeing asymptotic stability of the full order sliding mode dynamics. We also give an LMI characterization of the sliding surface, together with an integral sliding mode control law guaranteeing the existence of a sliding mode from the initial time. Additionally, we give an LMI condition of sliding surfaces guaranteeing the alpha-stability constraint. Finally, we give a simulation result to show the effectiveness of our method View full abstract»

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  • Output Feedback Boundary Control of a Ginzburg–Landau Model of Vortex Shedding

    Page(s): 742 - 748
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (459 KB) |  | HTML iconHTML  

    An exponentially convergent observer is designed for a linearized Ginzburg-Landau model of vortex shedding in viscous flow past a bluff body. Measurements are restricted to be taken collocated with the actuation which is applied on the cylinder surface. The observer is used in conjuction with a state feedback boundary controller designed in previous work to attenuate vortex shedding. While the theoretical results apply to the linearized system under sufficiently smooth initial data that satisfy the boundary conditions, simulations demonstrate the performance of the linear output feedback scheme on the nonlinear plant model View full abstract»

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  • Distributed Task Assignment for Mobile Agents

    Page(s): 749 - 753
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (209 KB) |  | HTML iconHTML  

    This note demonstrates how the distributed auction algorithm can be modified to assign mobile agents to spatially distributed tasks despite communication delays and the fact that agent movement may cause the benefit associated with each possible agent-task assignment to vary during the execution of the algorithm. Bounds on the convergence time of the algorithm and the sub-optimality of the resulting solution are provided. Monte Carlo simulations are provided to show the conditions under which the modified distributed auction can outperform centralized calculation View full abstract»

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  • QFT Templates for Plants With a High Number of Uncertainty Parameters

    Page(s): 754 - 758
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (325 KB) |  | HTML iconHTML  

    When uncertainty is given in parametric form, the QFT templates computation requires time if the number of parameters is high. The latest methods do not solve the problem efficiently. The present note shows a new way to calculate templates by means of analytic functions. The discrete template is replaced by an analytic template, so operations are done with functions, not with points. In such a way, the computation time is reduced and the results can be used to solve other problems such as bounds computation 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

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Meet Our Editors

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