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Automatic Control, IEEE Transactions on

Issue 1 • Date Jan. 1998

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Displaying Results 1 - 16 of 16
  • Robust Control Design: A Polynomial Approach [Book Reviews]

    Publication Year: 1998 , Page(s): 133 - 134
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    Freely Available from IEEE
  • Robust adaptive state-feedback tracking for nonlinear systems

    Publication Year: 1998 , Page(s): 84 - 89
    Cited by:  Papers (59)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (276 KB)  

    For a class of singie-input/single-output uncertain nonlinear systems, affected both by uncertain time-varying parameters (with known bounds) and unknown time-varying bounded disturbances, a new robust adaptive state-feedback control algorithm is presented. It guarantees: boundedness of all signals and arbitrary disturbance attenuation when both disturbances and time-varying parameters are present, and asymptotic tracking with arbitrary transient performance when no disturbance is acting on the system and parameters are constant. The adaptation may be switched off, still guaranteeing bounded signals and disturbance attenuation View full abstract»

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  • Stabilization and disturbance rejection for the wave equation

    Publication Year: 1998 , Page(s): 89 - 95
    Cited by:  Papers (17)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (244 KB)  

    We consider a system described by the one-dimensional linear wave equation in a bounded domain with appropriate boundary conditions. To stabilize the system, we propose a dynamic boundary controller applied at the free end of the system. The transfer function of the proposed controller is a proper rational function of the complex variable and may contain a single pole at the origin and a pair of complex conjugate poles on the imaginary axis, provided that the residues corresponding to these poles are nonnegative; the rest of the transfer function is required to be a strictly positive real function. We then show that depending on the location of the pole on the imaginary axis, the closed-loop system is asymptotically stable. We also consider the case where the output of the controller is corrupted by a disturbance and show that it may be possible to attenuate the effect of the disturbance at the output if we choose the controller transfer function appropriately. We also present some numerical simulation results which support this argument View full abstract»

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  • Mixed H2/H-control of discrete-time Markovian jump linear systems

    Publication Year: 1998 , Page(s): 95 - 100
    Cited by:  Papers (64)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (256 KB)  

    In this paper we consider the mixed H2/H-control problem for the class of discrete-time linear systems with parameters subject to Markovian jump linear systems. It is assumed that both the state variable and the jump variable are available to the controller. The transition probability matrix may not be exactly known, but belongs to an appropriate convex set. For this controlled discrete-time Markovian jump linear system, the problem of interest can be stated in the following way: find a robust (with respect to the uncertainty on the transition Markov probability matrix) mean-square stabilizing state and jump feedback controller that minimizes an upper bound for the H-norm, under the restriction that the H -norm is less than a prespecified value δ. The problem of the determination of the smallest H-norm is also addressed. We present an approximate version of these problems via linear matrix inequality optimization View full abstract»

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  • A general class of sliding surface for sliding mode control

    Publication Year: 1998 , Page(s): 115 - 119
    Cited by:  Papers (9)
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    In the conventional sliding mode control, the relative degree of the chosen sliding surface is usually one. This paper addresses a general class of sliding surface whose relative degree is no longer restricted to one. We show that when the relative degree is more than two, it is inevitable that there will exist a limit cycle for the nonlinear sign function. And for the case of relative degree two the system possesses poor phase margin. However, these disadvantages can be remedied remarkably by smoothing out the control nonlinearity in a suitable boundary layer with a saturation function that ensures asymptotic stability of the overall system View full abstract»

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  • Adaptive motion/force control of multiple manipulators with joint flexibility based on virtual decomposition

    Publication Year: 1998 , Page(s): 46 - 60
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (744 KB)  

    In this paper, a virtual decomposition-based adaptive motion/force control scheme is presented to deal with the control problem of coordinated multiple manipulators with flexible joints holding a common object in contact with the environment. The control scheme is essentially a generalized Newton-Euler approach in which the original system is virtually decomposed into several subsystems, including the held object, the rigid links, and the flexible joints, so that the control problem of the original system can be greatly simplified. An interesting result is that the dynamic coupling between every two physically connected subsystems is completely represented by the so-called virtual power flow (VPF) at the cutting point between them. The VPF takes a very simple form and is very easy to handle. Control design of the constraint/internal forces can be performed with respect to the held object. Asymptotic stability of the overall system is ensured in the sense of Lyapunov. Computer simulations of two manipulators transporting an object in the plane are given to show the validity of the proposed scheme View full abstract»

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  • Insensitive static-state feedback stabilization of a class of single-input linear systems by the condition numbers

    Publication Year: 1998 , Page(s): 108 - 115
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    The static-state feedback stabilization problem is considered for a class of single-input linear systems so that the closed-loop eigenvalues are as insensitive as possible to unstructured perturbations. Given a pair of complex conjugate numbers γ,γ * and a closed and bounded interval Γ of the real axis sufficiently far to the left of such a pair, a procedure for the design of a static-state feedback is given so that the closed-loop system has γ, γ* as the dominant pair of complex conjugate eigenvalues, while all the other eigenvalues are distinct and belong to Γ, with the sum of the squares of the condition numbers taking the minimum value View full abstract»

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  • Perturbation analysis of stochastic Petri nets

    Publication Year: 1998 , Page(s): 76 - 80
    Cited by:  Papers (1)
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    This paper addresses the sensitivity analysis of stochastic Petri nets (SPNs) using simulations. The goal is to evaluate the derivatives of performance measures with respect to timing parameters. To characterize the underlying stochastic processes of SPNs, we use a generalized semi-Markov process (GSMP) representation and propose a new representation, called GSMP*, which differs from GSMP in the routing mechanism. By using existing results on perturbation analysis of GSMPs and by extending them to GSMP*, unbiased sensitivity estimators are obtained for SPNs simulated under a GSMP or GSMP* framework. Most importantly, we prove that only one simulation run is needed for evaluating both the performance measures and their derivatives for a class of free-choice nets simulated under a GSMP framework and for any free-choice net simulated under a GSMP* framework View full abstract»

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  • Robust control of set-valued discrete-time dynamical systems

    Publication Year: 1998 , Page(s): 61 - 75
    Cited by:  Papers (12)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (888 KB)  

    This paper presents results obtained for the control of set-valued discrete-time dynamical systems. Such systems model nonlinear systems subject to persistent bounded noise. A robust control problem for such systems is introduced. The problem is formulated as a dynamic game, wherein the controller plays against the set-valued system. Both necessary and sufficient conditions in terms of (stationary) dynamic programming equalities are presented. The output feedback problem is solved using the concept of an information state, where a decoupling between estimation and control is obtained. The methods yield a conceptual approach for constructing controlled-invariant sets and stabilizing controllers for uncertain nonlinear systems View full abstract»

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  • Discrete-event control of nondeterministic systems

    Publication Year: 1998 , Page(s): 3 - 17
    Cited by:  Papers (34)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (564 KB)  

    Nondeterminism in discrete-event systems occurs in many practical situations and often as a result of partial observability of events. For the adequate description of nondeterministic systems and nondeterministic phenomena, the trajectory-model formalism was introduced by Heymann (1991) and Heymann et al. (1991). This formalism has been used in by Shayman et al. (1995) for obtaining various results on supervisory control of nondeterministic systems subject to language specifications. In the present paper we develop a theory of supervisory control for nondeterministic discrete-event systems subject to both language and trajectory-model specifications. We further show how well-known algorithms for supervisory control (of deterministic systems) under partial observation can be adapted for synthesis of supervisors for nondeterministic systems subject to both language and trajectory-model specifications View full abstract»

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  • Model quality evaluation in identification for H control

    Publication Year: 1998 , Page(s): 125 - 132
    Cited by:  Papers (2)
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    A mixed parametric-nonparametric approach to H identification is proposed, aimed at estimating a low-order approximating model and an identification error giving a measure of the model perturbation in a form well suited for H control methodologies. It is shown how to estimate the modeling errors of the identified parametric model and how to evaluate the performance values that can be guaranteed when the H controller is designed and applied to the real system. This performance value is then used for selecting the most “suitable” order of the parametric model class View full abstract»

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  • A parametrization of all the unfalsified plant models for MIMO systems

    Publication Year: 1998 , Page(s): 18 - 30
    Cited by:  Papers (1)
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    The results of the parametrization of all the unfalsified models for single-input/single-output systems are extended to multi-input/multi-output (MIMO) systems. In this parametrization, the assumed a priori plant and noise information are upper bounds of the H -norm of the plant matrix-valued transfer function and the noise magnitude. The parametrization is on the basis of several series of plant time-domain identification experiment data. It is shown that for MIMO systems, all the unfalsified plant matrix-valued transfer functions can still be expressed by the linear fractional transformation of a fixed matrix-valued transfer function and an H-norm bounded structure fixed, but uncertain matrix-valued transfer function. However, the high dimensions of the matrix-valued transfer functions involved in the parametrization hamper the direct application of these results to robust controller design. To overcome these difficulties, further efforts are needed View full abstract»

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  • An exact line search method for solving generalized continuous-time algebraic Riccati equations

    Publication Year: 1998 , Page(s): 101 - 107
    Cited by:  Papers (29)
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    We present a Newton-like method for solving algebraic Riccati equations that uses an exact line search to improve the sometimes erratic convergence behavior of Newton's method. It avoids the problem of a disastrously large first step and accelerates convergence when Newton steps are too small or too long. The additional work to perform the line search is small relative to the work needed to calculate the Newton step View full abstract»

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  • Static output feedback controllers: stability and convexity

    Publication Year: 1998 , Page(s): 120 - 125
    Cited by:  Papers (86)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (236 KB)  

    The main objective of this paper is to solve the following stabilizing output feedback control problem: given matrices (A; B2 ; C2) with appropriate dimensions, find (if one exists) a static output feedback gain L such that the closed-loop matrix A-B2LC2 is asymptotically stable. It is known that the existence of L is equivalent to the existence of a positive definite matrix belonging to a convex set such that its inverse belongs to another convex set. Conditions are provided for the convergence of an algorithm which decomposes the determination of the aforementioned matrix in a sequence of convex programs. Hence, this paper provides a new sufficient (but not necessary) condition for the solvability of the above stabilizing output feedback control problem. As a natural extension, we also discuss a simple procedure for the determination of a stabilizing output feedback gain assuring good suboptimal performance with respect to a given quadratic index. Some examples borrowed from the literature are solved to illustrate the theoretical results View full abstract»

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  • A unified framework for hybrid control: model and optimal control theory

    Publication Year: 1998 , Page(s): 31 - 45
    Cited by:  Papers (403)  |  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (608 KB)  

    We propose a very general framework that systematizes the notion of a hybrid system, combining differential equations and automata, governed by a hybrid controller that issues continuous-variable commands and makes logical decisions. We first identify the phenomena that arise in real-world hybrid systems. Then, we introduce a mathematical model of hybrid systems as interacting collections of dynamical systems, evolving on continuous-variable state spaces and subject to continuous controls and discrete transitions. The model captures the identified phenomena, subsumes previous models, yet retains enough structure to pose and solve meaningful control problems. We develop a theory for synthesizing hybrid controllers for hybrid plants in all optimal control framework. In particular, we demonstrate the existence of optimal (relaxed) and near-optimal (precise) controls and derive “generalized quasi-variational inequalities” that the associated value function satisfies. We summarize algorithms for solving these inequalities based on a generalized Bellman equation, impulse control, and linear programming View full abstract»

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  • Output feedback stabilization for uncertain systems: constrained Riccati approach

    Publication Year: 1998 , Page(s): 81 - 84
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (172 KB)  

    In this paper, the problem of output feedback stabilization of linear systems with mismatched uncertainties is investigated. A new approach to the design of output feedback controller is proposed, and the respective output feedback gains are obtained through the solution of a Riccati equation with linear constraints. Solvability conditions for such a constrained Riccati problem are derived, and a systematic algorithm for obtaining an output feedback controller, which guarantees the system state is globally exponentially stable, is provided 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