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Automatic Control, IEEE Transactions on

Issue 4 • Date April 1999

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Displaying Results 1 - 25 of 37
  • A Converse Lyapunov Theorem for a Class of Dynamical Systems which Undergo Switching

    Publication Year: 1999 , Page(s): 751 - 760
    Cited by:  Papers (216)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (458 KB)  

    The authors investigate the stability of a system in which the dynamics at any instant in time will follow one of a fixed set of vector fields. They allow switching between members of the family of vector fields to be completely random. The focus of this paper is to prove a converse Lyapunov theorem for this class of systems. View full abstract»

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  • Corrections to "A Method for the Synthesis of Controllers to Handle Safety, Liveness, and Real-Time Constraints" and "Tracking in Clutter with Strongest Neighbor Measurements - Part I: Theoretical Analysis"

    Publication Year: 1999 , Page(s): 886
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (32 KB)  

    Summary form only given. In the November 1998 issue, two recommending editors' names were unintentionally omitted. The information is as follows. The paper "A Method for the Synthesis of Controllers to Handle Safety, Liveness, and Real-Time Constraints," by Barbeau et al. (1998), was recommended by Associate Editor, F. Lin. In addition, the paper "Tracking in Clutter with Strongest Neighbor Measurements??Part I: Theoretical Analysis," by Li (1998), was recommended by Associate Editor, J. Spall. View full abstract»

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  • Advances in Aircraft Flight Control [Book Review]

    Publication Year: 1999 , Page(s): 887 - 889
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    Freely Available from IEEE
  • Robustness and performance of an indirect adaptive control scheme in presence of bounded disturbances

    Publication Year: 1999 , Page(s): 789 - 793
    Cited by:  Papers (17)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (196 KB)  

    Robustness and performances in the presence of disturbances of an indirect adaptive control scheme driven by the prediction error which is designed by organizing a sliding mode are examined in this paper. A new idea for performance improvement in the presence of disturbances is presented. The idea is applied to plants with unknown relative degree. It is proved that the proposed scheme can provide arbitrarily improved transient performances. The results are confirmed by simulation View full abstract»

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  • Feedback limitations in nonlinear systems: from Bode integrals to cheap control

    Publication Year: 1999 , Page(s): 829 - 833
    Cited by:  Papers (59)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (188 KB)  

    Feedback limitations of nonlinear systems are investigated using the cheap control approach. The main result is that in the limit, when the control effort is free, the smallest achievable L2 norm of the output is equal to the least amount of control energy (L2 norm) needed to stabilize the unstable zero dynamics. This nonlinear result is structurally similar to an earlier linear result by Qiu and Davison (1993), which, in turn, is connected with a Bode-type integral derived by Middleton (1991) View full abstract»

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  • A Popov criterion for systems with slowly time-varying parameters

    Publication Year: 1999 , Page(s): 844 - 846
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (180 KB)  

    A Popov criterion is derived for systems with slowly time-varying parameters. The parameters and their time derivatives are assumed to take values in convex polytopes View full abstract»

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  • Parametric H loopshaping and weighted mixed sensitivity minimization

    Publication Year: 1999 , Page(s): 846 - 852
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (300 KB)  

    Generalized H loopshaping is developed for a particular weighted mixed sensitivity minimization task. A free parameter is introduced to tradeoff minimizations of sensitivity and complementary sensitivity in the H performance index. A quadratically convergent algorithm is derived for computing the optimal performance index, and a state-space solution is obtained for suboptimal controllers. These results are applicable to stabilization of uncertain systems where normalized coprime factors involve parametrically weighted H norm-bounded perturbations. Controller reduction is also investigated for the parametric H loopshaping. Robust stability condition for using the reduced-order controller is established, and an estimate for the associated H performance is obtained. Similar results are derived for normalized linear quadratic Gaussian (LQG) control View full abstract»

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  • Gabor transform of time-varying systems: exact representation and approximation

    Publication Year: 1999 , Page(s): 729 - 741
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (616 KB)  

    Approximate modeling of discrete-time linear time-varying systems is studied based on a representation of linear systems in the Gabor time-frequency space. The time-varying system is assumed to be given in input-output or kernel representation. This representation has previously received attention because of its applicability in frozen-time analysis and design of optimal control for time-varying systems but requires a large number of coefficients. Motivated by its application to signal analysis, the Gabor transform is considered as a tool for the representation and approximation of linear time-variant systems. In order to show the main results, the class of systems considered is restricted to the one usually considered in the frozen-time approach. An example is included to illustrate the potential application of the technique View full abstract»

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  • Controllability of structured polynomial systems

    Publication Year: 1999 , Page(s): 761 - 764
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (176 KB)  

    Two algorithms, based on the Grobner basis method, which facilitate the controllability analysis for a class of polynomial systems are presented. The authors combine these algorithms with some results on output dead-beat controllability in order to obtain sufficient, as well as necessary, conditions for complete and state dead-beat controllability for a surprisingly large class of polynomial systems. Our results are generically applicable to the class of polynomial systems in strict feedback form View full abstract»

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  • Job flow control in assembly operations

    Publication Year: 1999 , Page(s): 864 - 868
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (176 KB)  

    The authors develop a state variable feedback control for a class of assembly operations. The objective of this control is to increase the number of jobs completed within a time horizon T while keeping the job cycle times within an acceptable range with a prespecified probability. The assembly operations are modeled as stochastic timed-event graphs which in the (max, +) algebra are characterized by a set of linear stochastic difference equations View full abstract»

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  • Minimum phase properties for input nonaffine nonlinear systems

    Publication Year: 1999 , Page(s): 868 - 872
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (212 KB)  

    For input nonaffine nonlinear control systems, the minimum phase property of the system in general depends on the control law. Switching or discontinuous controllers may offer advantages in this context. In particular, there may not exist a continuous control law which would keep the output identically equal to zero and for which the zero output constrained dynamics are locally stable, whereas a discontinuous controller which achieves this exists. For single-input/single-output input nonaffine nonlinear systems we give sufficient conditions for existence, and present a method for the design of discontinuous switching controllers which yield locally stable zero dynamics View full abstract»

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  • Single sample path-based sensitivity analysis of Markov processes using uniformization

    Publication Year: 1999 , Page(s): 872 - 875
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (188 KB)  

    Using the notion of perturbation realization factor, Cao and Chen (1997) provide sensitivity formulas of discrete-time Markov chains and uniformizable Markov processes. In this paper, the estimators of the realization factors of a uniformizable Markov process are provided by its uniformized Markov chain. It is proved that estimators given by the uniformized Markov chain have smaller variances than those provided by the original Markov process, which are increasing functions of the uniformization parameter and thus have minimal solutions View full abstract»

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  • A globally convergent frequency estimator

    Publication Year: 1999 , Page(s): 698 - 713
    Cited by:  Papers (117)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (600 KB)  

    Online estimation of the frequency of a sinusoidal signal is a classical problem in systems theory that has many practical applications. In this paper the authors provide a solution to the problem of ensuring a globally convergent estimation. More specifically, they propose a new adaptive notch filter whose dynamic equations exhibit the following remarkable features: 1) all signals are globally bounded and the estimated frequency is asymptotically correct for all initial conditions and all frequency values; 2) the authors obtain a simple tuning procedure for the estimator design parameters, which trades-off the adaptation tracking capabilities with noise sensitivity, ensuring (exponential) stability of the desired orbit; and 3) transient performance is considerably enhanced, even for small or large frequencies, as witnessed by extensive simulations. To reveal some of the stability-instability mechanisms of the existing algorithms and motivate our modifications the authors make appeal to a novel nonlinear (state-dependent) time scaling. The main advantage of working in the new time scale is that they remove the coupling between the parameter update law and the filter itself, decomposing the system into a feedback form where the required modifications to ensure stability become apparent. Even though they limit their attention here to the simplest case of a single constant frequency without noise the algorithm is able to track time-varying frequencies, preserve local stability in the presence of multiple sinusoids, and is robust with respect to noise View full abstract»

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  • Robust state feedback control of LTV systems: nonlinear is better than linear

    Publication Year: 1999 , Page(s): 802 - 807
    Cited by:  Papers (16)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (208 KB)  

    Examples of linear control systems with fast time-varying uncertain coefficients are given, which can be stabilized by a nonlinear memoryless state feedback, but cannot be stabilized by a linear time-invariant dynamic state feedback. By means of one of these examples the authors show that the closed loop quadratic stability margin may be infinitely smaller than the actual stability margin View full abstract»

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  • An exponentially stable adaptive control for force and position tracking of robot manipulators

    Publication Year: 1999 , Page(s): 798 - 802
    Cited by:  Papers (25)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (192 KB)  

    The problem of controlling a robot manipulator while the end effector is in contact with an environment of finite but unknown stiffness is considered. An exponentially stable control law is derived starting from a passivity-based position control algorithm. The original position trajectory is scaled along the interaction direction so as to achieve force tracking as well as position tracking along the unconstrained directions. A passivity-based adaptive algorithm is designed to avoid the explicit computation of the scaling factor, which depends on the unknown stiffness of the environment, leading to time-varying PID control actions on the force error View full abstract»

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  • A recursive algorithm for ARMAX model identification in closed loop

    Publication Year: 1999 , Page(s): 840 - 843
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (140 KB)  

    The joint problem of the recursive estimation of an optimal predictor for the closed-loop system and the unbiased parameter estimation of an ARMAX plant model in closed-loop operation is considered. A special reparameterized optimal predictor for the closed-loop is introduced. This allows a parameter estimation algorithm for the plant model to be derived which is globally asymptotically stable in a deterministic environment and gives asymptotically unbiased parameters estimates under richness conditions View full abstract»

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  • A switching adaptive controller for feedback linearizable systems

    Publication Year: 1999 , Page(s): 742 - 750
    Cited by:  Papers (38)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (544 KB)  

    One of the main open problems in the area of adaptive control of linear-in-the-parameters feedback linearizable systems is the computation of the feedback control law when the identification model becomes uncontrollable. The authors propose a switching adaptive control strategy that overcomes this problem. The proposed strategy is applied to nth-order feedback linearizable systems in canonical form. The closed-loop system is proved to be globally stable in the sense that all the closed-loop signals are bounded and the tracking error converges arbitrarily close to zero. No assumptions are made about the type of nonlinearities of the system, except that such nonlinearities are smooth. However, the proposed controller requires knowledge of the sign and lower bound of the input vector field View full abstract»

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  • Application of Laplace transformation for digital redesign of continuous control systems

    Publication Year: 1999 , Page(s): 883 - 886
    Cited by:  Papers (22)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (156 KB)  

    A frequency method of optimal digital re-design of an existing continuous-time system by a quadratic criterion is presented. The method is based on the use of Laplace transformation in continuous time and a parametrization of the set of admissible controllers. The proposed technique makes it possible to solve the optimization problem directly by employing input-output relations without an auxiliary passage to the state space. With such an approach the synthesis procedure is often greatly simplified. The method has the important feature that pure delays in the digital redesigned system can be taken into account in a simple way. It is shown that the presented method can be generalized onto different LQ-optimization problems for sampled-data systems View full abstract»

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  • Lur'e systems with multilayer perceptron and recurrent neural networks: absolute stability and dissipativity

    Publication Year: 1999 , Page(s): 770 - 774
    Cited by:  Papers (42)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (208 KB)  

    Sufficient conditions for absolute stability and dissipativity of continuous-time recurrent neural networks with two hidden layers are presented. In the autonomous case this is related to a Lur'e system with multilayer perceptron nonlinearity. Such models are obtained after parametrizing general nonlinear models and controllers by a multilayer perceptron with one hidden layer and representing the control scheme in standard plant form. The conditions are expressed as matrix inequalities and can be employed for nonlinear H control and imposing closed-loop stability in dynamic backpropagation View full abstract»

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  • Bounds on achievable performance in the identification and adaptive control of time-varying systems

    Publication Year: 1999 , Page(s): 670 - 682
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (520 KB)  

    Treats the identification and adaptive control of time-varying linear systems. For linear systems with a Gauss-Markov parameter process a global lower bound on the mean square error is obtained which is valid for any causal parameter estimator. A similar lower bound is obtained for any causal, one step-ahead predictor. These bounds are applied to the adaptive control of time-varying systems to obtain a lower bound on closed-loop mean square performance for any causal control law. For a specific control law, mean square stability is established, and through simulations it is seen that the performance nearly meets the theoretical lower bound View full abstract»

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  • Disturbance attenuation for systems with input saturation: An LMI approach

    Publication Year: 1999 , Page(s): 852 - 857
    Cited by:  Papers (49)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (280 KB)  

    A new design technique is proposed to improve disturbance attenuation for systems with input saturation. The main results rely on a multiobjective approach which combines the quadratic stabilization technique with constraints on inputs. For the full-state feedback problem, the sufficient conditions for the feasibility of a high-gain controller are expressed in terms of linear matrix inequalities (LMI). For output feedback design, the controllers are assumed to have an observer-based structure. The sufficient conditions for the output feedback controller to recover the full-state properties are also given in terms of LMI View full abstract»

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  • Frequency-domain optimization for robust fault detection and isolation in dynamic systems

    Publication Year: 1999 , Page(s): 878 - 882
    Cited by:  Papers (31)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (204 KB)  

    The paper deals with the design of optimal filters for fault detection and isolation (FDI) in dynamic systems. The proposed method, involving the generation of directional residuals derived from system's input-output description model, facilitates the enhancement of robustness even in cases where it is impossible to decouple fault effect from system perturbations. The proposed solution is based on the optimization of a performance index in the frequency domain. The resulting detection filter is capable of maximizing the effect of faults while minimizing the influence of disturbances View full abstract»

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  • Exact filters for doubly stochastic AR models with conditionally Poisson observations

    Publication Year: 1999 , Page(s): 794 - 798
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (208 KB)  

    The authors derive exact filters for the state of a doubly stochastic auto-regressive (AR) process with parameters which vary according to a nonlinear function of a Gauss-Markov process. The observations consist of a discrete-time Poisson process with rate a positive function of the Gauss-Markov process. The dimension of the sufficient statistic increases linearly with the number of observed events View full abstract»

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  • Decomposition and approximation of periodic systems

    Publication Year: 1999 , Page(s): 858 - 863
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (284 KB)  

    This paper proposes a decomposition of periodically time-varying systems in an attempt to reduce the often overwhelming number of modeling parameters involved. In many cases it would be possible to represent the system using only a few of those components. An a priori bound on the approximation error is derived in terms of the smoothness of the system parameters. Both continuous and discrete-time systems are considered View full abstract»

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  • Optimal average cost manufacturing flow controllers: convexity and differentiability

    Publication Year: 1999 , Page(s): 779 - 783
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (208 KB)  

    The authors consider the control of a production facility consisting of a single workstation with multiple failure modes and part types using a continuous flow control model. Technical issues concerning the convexity and differentiability of the differential cost function are investigated. It is proven that under an optimal control policy the differential cost is C1 on attractive control switching boundaries View full abstract»

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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