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Automatic Control, IEEE Transactions on

Issue 7 • Date July 2007

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Displaying Results 1 - 25 of 31
  • Table of contents

    Publication Year: 2007 , Page(s): C1 - C4
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    Freely Available from IEEE
  • IEEE Transactions on Automatic Control publication information

    Publication Year: 2007 , Page(s): C2
    Save to Project icon | Request Permissions | PDF file iconPDF (36 KB)  
    Freely Available from IEEE
  • Scanning the issue

    Publication Year: 2007 , Page(s): 1177 - 1178
    Save to Project icon | Request Permissions | PDF file iconPDF (35 KB) |  | HTML iconHTML  
    Freely Available from IEEE
  • Optimal LQ-Feedback Regulation of a Nonisothermal Plug Flow Reactor Model by Spectral Factorization

    Publication Year: 2007 , Page(s): 1179 - 1193
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1061 KB) |  | HTML iconHTML  

    The linear-quadratic (LQ) optimal temperature and reactant concentration regulation problem is studied for a partial differential equation model of a nonisothermal plug flow tubular reactor by using a nonlinear infinite dimensional Hilbert state space description. First the dynamical properties of the linearized model around a constant temperature equilibrium profile along the reactor are studied: it is shown that it is exponentially stable and (approximately) reachable. Next the general concept of LQ-feedback is introduced. It turns out that any LQ-feedback is optimal from the input-output viewpoint and stabilizing. For the plug flow reactor linearized model, a state LQ-feedback operator is computed via the solution of a matrix Riccati differential equation (MRDE) in the space variable. Thanks to the reachability property, the computed LQ-feedback is actually the optimal one. Then the latter is applied to the nonlinear model, and the resulting closed-loop system dynamical performances are analyzed. A criterion is given which guarantees that the constant temperature equilibrium profile is an asymptotically stable equilibrium of the closed-loop system. Moreover, under the same criterion, it is shown that the control law designed previously is optimal along the nonlinear closed-loop model with respect to some cost criterion. The results are illustrated by some numerical simulations. View full abstract»

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  • On the Achievable Delay Margin Using LTI Control for Unstable Plants

    Publication Year: 2007 , Page(s): 1194 - 1207
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (351 KB) |  | HTML iconHTML  

    Handling delays in control systems is difficult and is of long-standing interest. It is well known that, given a finite-dimensional linear time-invariant (FDLTI) plant and controller forming a strictly proper stable feedback connection, closed-loop stability will be maintained under a small delay in the feedback loop, although most closed loop systems become unstable for large delays. One previously unsolved fundamental problem in this context is whether, for a given FDLTI plant, an arbitrarily large delay margin can be achieved using LTI control. Here, we adopt a frequency domain approach and demonstrate that, for a strictly proper real rational plant, there is a uniform upper bound on the delay that can be tolerated when using an LTI controller, if and only if the plant has at least one closed right half plane pole not at the origin. We also give several explicit upper bounds on the achievable delay margin, and, in some special cases, demonstrate that these bounds are tight. View full abstract»

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  • Finite Differences in Homogeneous Discontinuous Control

    Publication Year: 2007 , Page(s): 1208 - 1217
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (469 KB) |  | HTML iconHTML  

    Finite differences are shown to be applicable to the on-line estimation of arbitrary-order derivatives in homogeneous discontinuous control. An output-feedback controller is produced from any finite-time-stable-sliding homogeneous controller, capable to control the output of any smooth uncertain single-input-single-output system of a known permanent relative degree . Variable sampling step feedback is proposed, in the absence of noises providing for the utmost -sliding accuracy corresponding to the minimal possible sampling interval. In the presence of noises the tracking accuracy is proportional to the unknown noise magnitude. Theoretical results are confirmed by computer simulation. View full abstract»

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  • Recursive Direct Weight Optimization in Nonlinear System Identification: A Minimal Probability Approach

    Publication Year: 2007 , Page(s): 1218 - 1231
    Cited by:  Papers (15)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (544 KB) |  | HTML iconHTML  

    In this paper, a direct weight optimization method is proposed for nonlinear system identification based on a minimal probability idea. The approach has several quite attractive features and is very different from existing ones. It is optimal for any given number of finite data points and at the same time possesses asymptotic convergence. The estimator admits a closed form and no numerical optimization is needed. Theoretical analysis and numerical simulations show that the approach is a very competitive alternative to existing nonlinear identification methods. View full abstract»

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  • Adaptive Learning Control of Nonlinear Systems by Output Error Feedback

    Publication Year: 2007 , Page(s): 1232 - 1248
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (704 KB) |  | HTML iconHTML  

    This paper addresses the problem of designing an output error feedback control for single-input, single-output nonlinear systems with uncertain, smooth, output-dependent nonlinearities whose local Lipschitz constants are known. The considered systems are required to be observable, minimum phase with known relative degree and known high frequency gain sign: linear systems are included. The reference output signal is assumed to be smooth and periodic with known period. By developing in Fourier series expansion a suitable periodic input reference signal, an output error feedback adaptive learning control is designed which ldquolearnsrdquo the input reference signal by identifying its Fourier coefficients: bounded closed loop signals and exponential tracking of both input and output reference signals are obtained when the Fourier series expansion is finite, while arbitrary small tracking errors are exponentially achieved otherwise. The resulting control is not model based, is independent of the system order and depends only on the relative degree, the reference signal period and the high frequency gain sign. View full abstract»

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  • Distributed Receding Horizon Control of Dynamically Coupled Nonlinear Systems

    Publication Year: 2007 , Page(s): 1249 - 1263
    Cited by:  Papers (43)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (971 KB) |  | HTML iconHTML  

    This paper considers the problem of distributed control of dynamically coupled nonlinear systems that are subject to decoupled constraints. Examples of such systems include certain large scale process control systems, chains of coupled oscillators and supply chain management systems. Receding horizon control (RHC) is a method of choice in these venues as constraints can be explicitly accommodated. In addition, a distributed control approach is sought to enable the autonomy of the individual subsystems and reduce the computational burden of centralized implementations. In this paper, a distributed RHC algorithm is presented for dynamically coupled nonlinear systems that are subject to decoupled input constraints. By this algorithm, each subsystem computes its own control locally. Provided an initially feasible solution can be found, subsequent feasibility of the algorithm is guaranteed at every update, and asymptotic stabilization is established. The theoretical conditions for feasibility and stability are shown to be satisfied for a set of coupled Van der Pol oscillators that model a walking robot experiment. In simulations, distributed and centralized receding horizon controllers are employed for stabilization of the oscillators. The numerical experiments show that the controllers perform comparably, while the computational savings of the distributed implementation over the centralized implementation is clearly demonstrated. View full abstract»

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  • Smooth Lyapunov Functions for Hybrid Systems—Part I: Existence Is Equivalent to Robustness

    Publication Year: 2007 , Page(s): 1264 - 1277
    Cited by:  Papers (27)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (759 KB) |  | HTML iconHTML  

    Hybrid systems are dynamical systems where the state is allowed to either evolve continuously (flow) on certain subsets of the state space or evolve discontinuously (jump) from other subsets of the state space. For a broad class of such systems, characterized by mild regularity conditions on the data, we establish the equivalence between the robustness of stability with respect to two measures and a characterization of such stability in terms of a smooth Lyapunov function. This result unifies and generalizes previous results for differential and difference inclusions with outer semicontinuous and locally bounded right-hand sides. Furthermore, we give a description of forward completeness of a hybrid system in terms of a smooth Lyapunov-like function. View full abstract»

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  • Integral High-Order Sliding Modes

    Publication Year: 2007 , Page(s): 1278 - 1282
    Cited by:  Papers (43)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (216 KB) |  | HTML iconHTML  

    Integral sliding mode approach is extended to high-order sliding modes (HOSMs), and allows choosing transient dynamics, or assigning a transient-time function of initial conditions. The resulting controller is robust and capable of controlling outputs of uncertain smooth SISO systems of a known permanent relative degree. The control smoothness can be deliberately increased. View full abstract»

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  • An Alternative Nonlinear Control Law for the Global Stabilization of the PVTOL Vehicle

    Publication Year: 2007 , Page(s): 1282 - 1287
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (203 KB) |  | HTML iconHTML  

    A popular method for the control of the planar vertical takeoff and landing vehicle (PVTOL) is to cast the system into the form of a cascade nonlinear system with an exponentially stable linear subsystem, as suggested by Olfati-Saber in 2002. This idea has since been incorporated into many other published works. The contribution of this note is to demonstrate an alternative cascade structure, achieved by minimizing the interconnection term between closed-loop subsystems. Global stability of the proposed controller is proven, and simulation results suggest improved performance of this new approach as compared to that previously published. View full abstract»

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  • On Necessary and Sufficient Conditions for H Output Feedback Control of Markov Jump Linear Systems

    Publication Year: 2007 , Page(s): 1287 - 1292
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (238 KB) |  | HTML iconHTML  

    This note addresses the output feedback Hinfin control problem for continuous-time Markov jump linear systems. It is shown that the feasibility of a certain set of linear matrix inequalities is both sufficient and necessary for the existence of a solution. Under standard assumptions, we also give a Riccati-type sufficient and necessary condition for an Hinfin-suboptimal controller to exist. View full abstract»

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  • Array Algorithm for Filtering of Discrete-Time Markovian Jump Linear Systems

    Publication Year: 2007 , Page(s): 1293 - 1296
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (188 KB) |  | HTML iconHTML  

    This note develops an array algorithm for optimal filtering of discrete-time Markovian jump linear systems (DTMJLSs). The known advantages of this kind of algorithm, which was originally developed for normal state-space systems, remain valid when it is applied to linear systems subject to Markovian jumps. It is numerically more stable in the sense that it presents better conditioning and reduced dynamical range. A numerical example, based on fixed-point implementations, is presented in order to demonstrate the advantage of this algorithm. View full abstract»

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  • Navigation Functions on Cross Product Spaces

    Publication Year: 2007 , Page(s): 1297 - 1302
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1188 KB) |  | HTML iconHTML  

    Given two compact, connected manifolds with corners, and a navigation function (NF, a refined artificial potential function) on each manifold, this paper presents a simple composition law that yields a new NF on the cross product space. The method provides tunable ldquohooksrdquo for shaping the new potential function while still guaranteeing obstacle avoidance and essentially global convergence. The composition law is associative, and successive compositions fold into a single, computational simple expression, enabling the practical construction of NFs on the Cartesian product of several manifolds. View full abstract»

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  • How to Tell a Bad Filter Through Monte Carlo Simulations

    Publication Year: 2007 , Page(s): 1302 - 1307
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (329 KB) |  | HTML iconHTML  

    In this note, we propose one particular method to address the issue of how to numerically evaluate nonlinear filtering algorithms and/or their software implementations, through Monte Carlo simulations. We introduce a quantitative performance indicator whose computation can be automated and does not depend on any specific definition of point estimate. The method is based on conditional probability integral transform and maximum deviation of an empirical cumulative distribution function from a uniform distribution. The usefulness of such an indicator is illustrated through an example. View full abstract»

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  • On Improving Transient Performance in Tracking Control for a Class of Nonlinear Discrete-Time Systems With Input Saturation

    Publication Year: 2007 , Page(s): 1307 - 1313
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1698 KB) |  | HTML iconHTML  

    Quick response and small overshoot are two desired transient performances of target tracking control. While most of the design schemes compromise between these two performances, we try to achieve both simultaneously for the tracking control of a class of nonlinear discrete-time systems with input saturation by using a composite nonlinear feedback (CNF) control technique. The closed-loop system with improved transient performance preserves the stability of the nonlinear part of the partially linear composite system. View full abstract»

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  • Design of Networked Control Systems With Packet Dropouts

    Publication Year: 2007 , Page(s): 1314 - 1319
    Cited by:  Papers (113)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (376 KB) |  | HTML iconHTML  

    This note is concerned with stability and controller design of networked control systems (NCSs) with packet dropouts. New NCS models are provided considering both single- and multiple-packet transmissions. Both sensor-to-controller (S/C) and controller-to-actuator (C/A) packet dropouts are modeled and their history behavior is described by different independent Markov chains. In term of the given models, sufficient conditions for stochastic stability are derived in the form of linear matrix inequalities (LMIs) and corresponding control laws are given. Numerical examples illustrate the effectiveness of the results. View full abstract»

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  • Spectral Method for Analysis of Switching Diffusions

    Publication Year: 2007 , Page(s): 1320 - 1325
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (532 KB) |  | HTML iconHTML  

    The analysis problem of switching diffusions is considered. This paper presents a new approach based on the spectral method formalism for solving generalized Fokker-Planck equations. The proposed method allows to transform partial differential equations into the linear algebraic equations, and to arrive at a solution in an explicit form. The aspects of applications are discussed. A numerical example is given to illustrate the efficiency of the proposed method. View full abstract»

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  • Nonlinear Observers for Unicycle Robots With Range Sensors

    Publication Year: 2007 , Page(s): 1325 - 1329
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (722 KB) |  | HTML iconHTML  

    For nonlinear mobile systems equipped with exteroceptive sensors, the observability does not only depend on the initial conditions, but also on the control and the environment. This presents an interesting issue: how to design an observer together with the exciting control. In this note, the problem of designing an observer based on range sensor readings is studied. A design method based on periodic excitations is proposed for unicycle robotic systems. View full abstract»

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  • Analysis of Positive Invariance and Almost Regional Attraction Via Density Functions With Converse Results

    Publication Year: 2007 , Page(s): 1329 - 1333
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (351 KB) |  | HTML iconHTML  

    This note is concerned with analysis of positive invariance of nonlinear systems and convergence of trajectories in a region of the state-space via density functions. If there exists a density function that is positive inside a set containing an equilibrium point and tends to zero as approaches to the boundary, the set is positively invariant and almost all of the trajectories starting from there converge to the equilibrium. Converse results are also provided to prove the existence of such density functions. View full abstract»

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  • Parameter-Dependent LMIs in Robust Analysis: Characterization of Homogeneous Polynomially Parameter-Dependent Solutions Via LMI Relaxations

    Publication Year: 2007 , Page(s): 1334 - 1340
    Cited by:  Papers (73)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1051 KB) |  | HTML iconHTML  

    This note investigates the robust stability of uncertain linear time-invariant systems in polytopic domains by means of parameter-dependent linear matrix inequality (PD-LMI) conditions, exploiting some algebraic properties provided by the uncertainty representation. A systematic procedure to construct a family of finite-dimensional LMI relaxations is provided. The robust stability is assessed by means of the existence of a Lyapunov function, more specifically, a homogeneous polynomially parameter-dependent Lyapunov (HPPDL) function of arbitrary degree. For a given degree , if an HPPDL solution exists, a sequence of relaxations based on real algebraic properties provides sufficient LMI conditions of increasing precision and constant number of decision variables for the existence of an HPPDL function which tend to the necessity. Alternatively, if an HPPDL solution of degree exists, a sequence of relaxations which increases the number of variables and the number of LMIs will provide an HPPDL solution of larger degree. The method proposed can be applied to determine homogeneous parameter-dependent matrix solutions to a wide variety of PD-LMIs by transforming the infinite-dimensional LMI problem described in terms of uncertain parameters belonging to the unit simplex in a sequence of finite-dimensional LMI conditions which converges to the necessary conditions for the existence of a homogeneous polynomially parameter-dependent solution of arbitrary degree. Illustrative examples show the efficacy of the proposed conditions when compared with other methods from the literature. View full abstract»

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  • A Simple Nonlinear Observer for a Class of Uncertain Mechanical Systems

    Publication Year: 2007 , Page(s): 1340 - 1345
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1186 KB) |  | HTML iconHTML  

    A simple nonlinear observer is proposed for a class of uncertain nonlinear multiple-input-multiple-output (MIMO) mechanical systems whose dynamics are first-order differentiable. The global asymptotic observation of the proposed observer is proved. Thus, the observer can be designed independently of the controller. Furthermore, the proposed observer is formulated without any detailed model knowledge of the system. These advantages make it easy to implement. Numerical simulations are included to illustrate the effectiveness of the proposed observer. View full abstract»

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  • On Linear Copositive Lyapunov Functions and the Stability of Switched Positive Linear Systems

    Publication Year: 2007 , Page(s): 1346 - 1349
    Cited by:  Papers (39)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (174 KB) |  | HTML iconHTML  

    We consider the problem of common linear copositive Lyapunov function existence for positive switched linear systems. In particular, we present a necessary and sufficient condition for the existence of such a function for switched systems with two constituent linear time-invariant systems. Several applications of this result are also given. View full abstract»

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  • Recursive Learning Automata Approach to Markov Decision Processes

    Publication Year: 2007 , Page(s): 1349 - 1355
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (375 KB) |  | HTML iconHTML  

    In this note, we present a sampling algorithm, called recursive automata sampling algorithm (RASA), for control of finite-horizon Markov decision processes (MDPs). By extending in a recursive manner Sastry's learning automata pursuit algorithm designed for solving nonsequential stochastic optimization problems, RASA returns an estimate of both the optimal action from a given state and the corresponding optimal value. Based on the finite-time analysis of the pursuit algorithm by Rajaraman and Sastry, we provide an analysis for the finite-time behavior of RASA. Specifically, for a given initial state, we derive the following probability bounds as a function of the number of samples: 1) a lower bound on the probability that RASA will sample the optimal action and 2) an upper bound on the probability that the deviation between the true optimal value and the RASA estimate exceeds a given error. 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