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Automatic Control, IEEE Transactions on

Issue 5 • Date May 1990

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Displaying Results 1 - 25 of 27
  • Optimal filtering of FIR prefiltered data

    Publication Year: 1990 , Page(s): 608 - 610
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (252 KB)  

    Given limited computational resources and/or superfluous states in the system model, it is possible to lower computational requirements and/or to diminish the influence of the extra states upon the output of the system by prefiltering the data through a conventional filter before processing them through an optimal filter algorithm. A prefilter-compensated system model is developed which maintains a one-to-one correspondence with the original model which is constructed to represent the system before the prefilter is applied. For the case where the weighting is performed upon the output of a linear shift invariant (LSI) discrete-time system, a system description can be derived which fully characterizes the state and prefiltered measurement, without increasing the dimension of the original system. In the case of a nonlinear system, a compensated system description can be formulated in a similar manner. Thus, state estimates obtained using this model are likely to be significantly improved over those obtained using less accurate models View full abstract»

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  • The simultaneous optimization problem for sensitivity and gain margin

    Publication Year: 1990 , Page(s): 558 - 563
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (504 KB)  

    The combined sensitivity and gain margin problem for single-input single-output linear systems is formulated and solved using a complex function interpolation technique. It is proved that this problem always has a real rational solution provided it is solvable in the complex irrational sense. The sensitivity minimization problem subject to a gain margin constraint and its dual problem are also considered. The range of the gain margin constraint is given subject to which the optimal constrained sensitivity is identical with the optimal unconstrained sensitivity. It is shown that, not unexpectedly, the gain margin maximization conflicts with the sensitivity minimization for a nonminimum phase plant View full abstract»

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  • A unifying theorem for linear and total linear least squares

    Publication Year: 1990 , Page(s): 563 - 566
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (356 KB)  

    It is shown how both linear least-squares and total linear least-squares estimation schemes are special cases of a rank one modification of the data matrix or the sample covariance matrix. For a problem with n unknowns, there exist n linear least-squares solutions while the total linear least-squares solution is (generically) unique. When the signal-to-noise ratio is sufficiently high, the total least-squares solution is a nonnegative combination of the least-squares solutions View full abstract»

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  • A Hamiltonian-Jacobi algorithm

    Publication Year: 1990 , Page(s): 566 - 570
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (452 KB)  

    The nonsymmetric Jacobi iteration is adapted to the special structure of Hamiltonian matrices. This Hamiltonian-Jacobi algorithm uses symplectic-unitary similarity transformations to solve algebraic Riccati equations through the Hamiltonian-Schur form. It preserves Hamiltonian structure without using a condensed form. Although it converges too slowly for use on conventional serial computers, it may be attractive for some highly parallel architectures View full abstract»

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  • On the stabilization and observation of nonlinear/uncertain dynamic systems

    Publication Year: 1990 , Page(s): 604 - 607
    Cited by:  Papers (28)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (320 KB)  

    The problem of stabilization and observation of uncertain and/or nonlinear dynamic systems for which matching conditions are not satisfied is investigated. No statistical description of uncertain elements is assumed. The uncertain and/or nonlinear quantities are described only in terms of bounds on their possible sizes. Stabilizing feedback controllers and observers are proposed whose design is based on the constructive use of Lyapunov functions and the Bellman-Gronwall lemma View full abstract»

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  • Almost disturbance decoupling by measurement feedback: a frequency domain analysis

    Publication Year: 1990 , Page(s): 570 - 573
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (404 KB)  

    The almost disturbance decoupling problem by measurement feedback if formulated for systems described by transfer matrices. Necessary and sufficient conditions for the solvability of the problem are given in frequency-domain terms. The conditions are derived using frequency-domain techniques only View full abstract»

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  • Adaptive control for robot manipulators using discrete time identification

    Publication Year: 1990 , Page(s): 633 - 637
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (408 KB)  

    An adaptive control scheme is proposed for rigid link robots where the control signal computations are performed continuously and the control coefficient computations are performed in discrete time. A global boundedness result is established for the resulting scheme, independent of the sampling rate. It is also shown that the position, velocity, and acceleration tracking errors are of the order of the sampling period. Furthermore, it is shown that, if the reference trajectory is persistently exciting (in a continuous-time sense), then, for a sufficiently fast sampling rate, the tracking errors decay to zero View full abstract»

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  • Synthesis of feedback control logic for a class of controlled Petri nets

    Publication Year: 1990 , Page(s): 514 - 523
    Cited by:  Papers (141)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1088 KB)  

    An efficient solution is developed for a class of forbidden state problems for discrete event systems (DESs). DESs are considered which can be modeled as cyclic controlled marked graphs (CMGs), a special class of controlled Petri nets (CPNs). The distributed representation of the DES state in terms of the CMG marking permits an efficient specification of the forbidden states in terms of individual place markings. More important, it is shown that the graphical representations of the state transition logic in a CMG can be used to synthesize state feedback logic which is maximally permissive while guaranteeing the forbidden states will not occur. The practical application of the theoretical results is illustrated for an example of automated guided vehicle (AGV) coordination in a flexible manufacturing facility View full abstract»

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  • On fault-tolerant observers

    Publication Year: 1990 , Page(s): 623 - 627
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (240 KB)  

    The problem of designing asymptotic observers for multioutput systems with one unreliable output measurement is addressed. It is shown that observers designed on the basis of observability indexes are not fault tolerant, and an observer for linear systems which tolerates failures in one a priori known output is given. The results are extended to nonlinear systems with no inputs: it is pointed out that the proposed design procedure may enlarge the class of nonlinear systems for which a nonlinear observer can be obtained View full abstract»

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  • Invariance of the aperiodic property for polynomials with perturbed coefficients

    Publication Year: 1990 , Page(s): 616 - 618
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (212 KB)  

    A procedure for obtaining the maximal intervals of the coefficients for a perturbed polynomial to be still strictly aperiodic is presented. Lemmas, theorems, and proofs are given. An illustrative example is presented View full abstract»

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  • Discrete time robust control via state feedback for single input systems

    Publication Year: 1990 , Page(s): 590 - 598
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (496 KB)  

    A nonlinear robust state feedback controller for discrete-time uncertain systems is proposed. The uncertainties in the system must satisfy the matching condition, but only their bounds need to be known. The controller is designed via the second method of Lyapunov. The detailed derivation of the controller for single-input systems is given. The system response remains in the neighborhood of the zero state if uncertainties are small. The uncertainty bound for the stability condition is derived View full abstract»

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  • Extended optimality properties of the linear quadratic regulator and stationary Kalman filter

    Publication Year: 1990 , Page(s): 583 - 585
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (232 KB)  

    It is shown that the constant gain state-feedback solution to the infinite-time linear quadratic regulator problem is optimal not only for arbitrarily initial conditions or white noise disturbances, but also for worst-case L1 disturbances. Using a similar technique, it is shown that in the stationary Kalman filter, the white disturbance and measurement noise can be replaced by unknown bounded energy signals, and that optimality still holds if the performance criterion is a time domain L normal of the state estimation errors in the presence of worst-case energy signals View full abstract»

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  • Constrained minimum-time path planning for robot manipulators via virtual knots of the cubic B-spline functions

    Publication Year: 1990 , Page(s): 573 - 577
    Cited by:  Papers (15)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (376 KB)  

    The B-spline functions are used to generate the constrained minimum-time path for a robot manipulator. The interpolated path via B-spline functions is determined via a unique set of virtual knots so that the robot path can pass every intermediate knot and satisfy the boundary conditions. The local control property of the B-spline functions can also be utilized to simplify the involved computational complexities. The flexible polyhedron search algorithm is used to generate the near minimum-time path with velocity, acceleration, and jerk constraints on every intermediate point. This approach can simplify the formulation and procedures for generating the near minimum-time cubic B-spline path. The use of this method to generate the constrained minimum-time joint trajectories for a PUMA 560 robot is discussed as an example View full abstract»

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  • Homogeneous, asymptotically reliable serial production lines: theory and a case study

    Publication Year: 1990 , Page(s): 524 - 534
    Cited by:  Papers (15)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (836 KB)  

    A model of homogeneous, asymptotically reliable serial production lines is introduced, analyzed, and applied to the problem of performance evaluation of a modular paint shop at an automobile assembly plant. The results obtained indicate that the homogeneous, asymptotically reliable production lines are, on the one hand, simpler for analysis than traditional models and, on the other, sufficiently rich to reflect the behavior of real manufacturing systems. The asymptotic theory developed gives analytical formulas for production rates as a function of system parameters and, therefore, can be used as an inexpensive tool for the analysis and design of manufacturing processes in mass production systems, eliminating, in some cases, the necessity of complex and costly computer simulations View full abstract»

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  • H-minimum error state estimation of linear stationary processes

    Publication Year: 1990 , Page(s): 554 - 558
    Cited by:  Papers (70)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (392 KB)  

    A state estimator is derived which minimizes the H-norm of the estimation error power spectrum matrix. Two approaches are presented. The first achieves the optimal estimator in the frequency domain by finding the filter transfer function matrix that leads to an equalizing solution. The second approach establishes a duality between the problem of H-filtering and the problem of unconstrained input H-optimal regulation. Using this duality, previously published results for the latter regulation problem are applied which lead to an optimal filter that possess the structure of the corresponding Kalman filter. The two approaches usually lead to different results. They are compared by a simple example which also demonstrates a clear advantage of the H-estimate over the conventional l 2-estimate View full abstract»

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  • Robustness of stochastic-parameter control and estimation schemes

    Publication Year: 1990 , Page(s): 637 - 640
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (328 KB)  

    The effects on closed-loop system stability of modeling errors resulting from overestimating or underestimating the statistical characteristics in linear discrete-time stochastic parameter systems are investigated. Both infinite and moving horizon controllers designed using erroneous parameter characteristics, which can preserve the mean-square and almost sure boundedness of the close-loop system state, are considered. Mean-square, optimal linear, unbiased one-step predictors are shown to possess stability robustness even when designed with the wrong parameter characteristics View full abstract»

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  • Necessary and sufficient conditions of quadratic stability of uncertain linear systems

    Publication Year: 1990 , Page(s): 601 - 604
    Cited by:  Papers (21)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (332 KB)  

    The stability of linear systems subject to possibly fast time-varying uncertainties is analyzed. A necessary and sufficient condition of quadratic stability is derived. An uncertainty stability margin coefficient ρ is introduced to give a quantitative measure of the stability. It is proposed that the uncertain region be approximated by a convex hyperpolyhedron. In this case, the computation of ρ becomes a two-level optimization problem, in which the extremum of the inner level can be reached by one of the corners of the hyperpolyhedron View full abstract»

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  • On the convergence of the self-tuning algorithms based on nonmodified least-squares

    Publication Year: 1990 , Page(s): 628 - 633
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (440 KB)  

    Self-tuning servo control based on a nonmodified least-squares algorithm is considered. The fundamental result of the analysis is that the passivity of the two time-varying operators depending on the noise process dynamics, regression vector, and the ponderation matrix sequence of the algorithm is essential for the global stability of the self-tuning regulator. The methodology can be applied to problems of adaptive prediction based on a nonmodified least-squares algorithm and system parameter identification by a least-squares algorithm with a priori prediction View full abstract»

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  • Invariant spaces at infinity of linear systems application to block decoupling

    Publication Year: 1990 , Page(s): 618 - 623
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (448 KB)  

    The dynamic state feedback block decoupling problem in the general case, i.e. with singular or nonsingular input transformations, is solved. It is proven that the problem is solvable if the number of inputs is large enough. The main tools for this study are some invariant spaces associated with the columns infinite behavior of a rational matrix. It turns out that when the problem is solvable, it is also solvable with stability View full abstract»

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  • The construction of special coprime factorizations in discrete time

    Publication Year: 1990 , Page(s): 588 - 590
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (244 KB)  

    Given a rational, discrete-time transfer matrix, it is shown how to construct two special kinds of coprime factorizations for it-normalized and all-pass denominator. This is done in two ways. First, by carrying the existing continuous-time construction results to discrete-time via a bilinear transformation. This is shown to be messy and computationally burdensome. Second, direct constructions are derived in discrete time. The derivations point out interesting differences between discrete and continuous time for these constructions View full abstract»

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  • Least-informative Bayesian prior distributions for finite samples based on information theory

    Publication Year: 1990 , Page(s): 580 - 583
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (368 KB)  

    A procedure is presented, based on Shannon information theory, for producing least-informative prior distributions for Bayesian estimation and identification. This approach relies on constructing an optimal mixture distribution and applies in small sample sizes (unlike certain approaches based on asymptotic theory). The procedure is illustrated in a small-scale numerical study and is contrasted with an approach based on maximum entropy View full abstract»

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  • Loop transfer recovery for nonminimum phase plants

    Publication Year: 1990 , Page(s): 547 - 553
    Cited by:  Papers (33)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (648 KB)  

    A study of what happens when the loop transfer recovery (LTS) procedure is applied to nonminimum-phase (NMP) plants, how design limitations due to right-half-plane zeros manifest themselves in the LTR procedure, and how this knowledge can be incorporated into design is presented. Explicit expressions are given for the asymptotic behavior of the loop transfer and sensitivity functions resulting from application of the LTR procedure to nonminimum-phase plants. It is shown that there exists a tradeoff between the feedback properties of the state feedback loop and the ability to recover those properties using the LTR procedure View full abstract»

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  • Recursive functional series modeling estimators for identification of time-varying plants-more bad news than good?

    Publication Year: 1990 , Page(s): 610 - 616
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (568 KB)  

    The properties of a class of recursive estimators-the exponentially weighted functional series modeling estimators-are discussed. These estimators can be used, e.g. in adaptive prediction or control applications. It is argued that there exists a relationship between the amount of information about time-varying system parameters, which is available a priori, and the robustness of the identification algorithm based on such prior knowledge. The more specialized the estimation algorithm is, the less reliable it might be under nonstandard conditions. This is the reason why simple algorithms such as exponentially weighted least squares have to be recommended as if no information about the system nonstationarity is available in advance View full abstract»

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  • On minimizing maximum errors

    Publication Year: 1990 , Page(s): 598 - 601
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (248 KB)  

    It is shown how a previously published control problem by A.G. Parlos (1988) formulated using ellipsoidal set-theoretic control synthesis techniques can be formulated and solved using l1 optimal control theory. A complete solution is furnished to the problem. It avoids the difficulties of parameter optimization View full abstract»

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  • Fast stability checking for the convex combination of stable polynomials

    Publication Year: 1990 , Page(s): 586 - 588
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (284 KB)  

    A fast algorithm is proposed for checking the stability of the edges of a polytope where most of the computations involved depend on the number of vertices rather than on the number of edges. This algorithm is based on the segment lemma derived by H. Chapellat et al. (1988). Although the segment lemma is an important result on its own, no explicit algorithm was given there. Some important properties of the lemma are revealed, and it is shown how they lead to a fast algorithm. In this algorithm, the major computations involved are those of solving for the positive real roots of two polynomials with degree less than or equal to n/2 for each vertex. The computations required by the algorithm are mainly vertex-dependent, and the burden of the combinatoric explosion of the number of edges is greatly reduced 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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Editor-in-Chief
P. J. Antsaklis
Dept. Electrical Engineering
University of Notre Dame