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Automatic Control, IEEE Transactions on

Issue 12 • Date Dec 1993

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Displaying Results 1 - 14 of 14
  • State-space solution of the causal factorization problem

    Publication Year: 1993 , Page(s): 1843 - 1848
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (448 KB)  

    Given rational matrix functions, G, H, and R, a necessary and sufficient condition is given for the existence of a causal solution to the equation GXH=R. A formula is given for a solution of the equation when it exists, and this particular solution is used to parameterize the set of all causal solutions of the equation. The results are specialized to the case when the function G is identically equal to identity. Applications of the author's results include exact model matching and disturbance decoupling problems View full abstract»

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  • New results about Morgan's problem

    Publication Year: 1993 , Page(s): 1834 - 1838
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (400 KB)  

    Some aspects of the nonsquare Morgan's problem are considered. In particular, it is shown that the condition given by J. Descusse et al. (1986) to solve this problem is not sufficient. It is also shown that the essential orders are not necessarily preserved in the static decoupling problem. A necessary and sufficient condition for static decoupling of a system without modifying the essential orders is given for the case k=p-1. where p is the number of outputs and k is the rank at infinity of the proper part of the interactor View full abstract»

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  • Wiener-Hopf design of optimal decoupled multivariable feedback control system

    Publication Year: 1993 , Page(s): 1838 - 1843
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (432 KB)  

    An important consideration in the design of many control systems is decoupling (each command input controlling only one output). The 2DOF (two-degree-of-freedom) or 3DOF (three-degree-of-freedom) structure is ideally suited to this task since only one of the degrees of freedom is affected by the decoupling requirement. The decoupling constraint on this degree of freedom, however, can lead to some deterioration in achievable system performance. A design procedure which minimizes this performance deterioration is established. The parameterization of the class of all decoupled systems is given for which the cost functional representing system performance remains finite View full abstract»

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  • New robustness bounds for discrete systems with random perturbations

    Publication Year: 1993 , Page(s): 1866 - 1870
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (272 KB)  

    Some new stochastic stability robustness bounds for state-space models are reported. Nominally exponentially stable discrete-time systems are assumed to be subject to random parameter perturbations and novel bounds are obtained on the maximum variances of these random perturbations to maintain stability robustness. The methods employed in the analysis are the existing ones used in the deterministic framework after transforming the stochastic robustness problem to a deterministic one. The results are compared with each other and with the exact stability region in an example View full abstract»

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  • A behavioral approach to linear exact modeling

    Publication Year: 1993 , Page(s): 1776 - 1802
    Cited by:  Papers (22)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1740 KB)  

    The behavioral approach to system theory provides a parameter-free framework for the study of the general problem of linear exact modeling and recursive modeling. The authors present the solution of the (continuous-time) polynomial-exponential time series modeling problem. Both recursive and nonrecursive solutions are provided and classified according to properties like complexity and controllability. It is shown, in particular, that recursive modeling corresponds to updating by means of a cascade inter-connection of systems. As a special case, the solution of several other problems, such as rational interpolation, realization, and modeling of arbitrary discrete-time time series, is obtained View full abstract»

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  • Robust and adaptive supervisory control of discrete event systems

    Publication Year: 1993 , Page(s): 1848 - 1852
    Cited by:  Papers (34)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (372 KB)  

    Both robust and adaptive supervisory control in discrete-event systems are discussed. It is assumed that the system G to be controlled is not known exactly. It is only known either that it belongs to a set or that it has certain lower and upper bounds. The task of robust supervision is to synthesize a supervisor that realizes a given desired behavior for all possible G. A necessary and sufficient condition for the existence of such a robust supervisor is derived. Based on this condition, a robust supervisory control and observation problem of synthesizing a robust supervisor whose behavior is both legal and acceptable is solved. Adaptive supervision is discussed. As the system progresses, the information on occurrences of events may help to resolve or reduce uncertainties View full abstract»

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  • Robustness of discrete-time adaptive controllers: an input-output approach

    Publication Year: 1993 , Page(s): 1852 - 1857
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (376 KB)  

    A general input-output approach that can be used for the design and analysis of robust discrete-time adaptive control schemes is presented. In particular, a model reference adaptive controller is considered. The design approach involves the use of the certainty equivalence principle to combine a robust control structure with a robust adaptive law. Using exponentially weighted I2 norms and exploiting the properties of the adaptive law and the control structure, robust stability is established for the closed-loop adaptive control scheme View full abstract»

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  • Covariance averaging in the analysis of uncertain systems

    Publication Year: 1993 , Page(s): 1858 - 1862
    Cited by:  Papers (5)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (364 KB)  

    The effects of parametric uncertainty in stable state-space systems are analyzed by averaging the state covariance over the statistics of the uncertain parameters. For natural frequency uncertainty, this computation is related to the Fourier transform of the probability density function of the uncertain parameter. Equipartition and incoherence are illustrated for a single-mode oscillator. Averaging over a discrete uncertainty model yields the Bourret design equations while averaging over a Cauchy uncertainty distribution yields the maximum-entropy covariance equation of D.C. Hyland (1982) View full abstract»

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  • Stabilizability and stabilization of a rotating body-beam system with torque control

    Publication Year: 1993 , Page(s): 1754 - 1765
    Cited by:  Papers (19)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (612 KB)  

    The stabilizability and stabilization of a rotating body-beam system with torque control are discussed. This system has a linear inertial manifold. An operator-theoretic argument is used to provide an alternative proof of this fact. By taking into account the effect of damping (structural or viscous), the stability result of J. Baillieul and M. Levi (1987) is proved using the LaSalle principle (1968). It is shown that there exists a critical angular velocity for the use of torque control to stabilize the system in the neutral configuration with constant angular velocity. For any constant angular velocity smaller than the critical one a feedback torque control law is given which exponentially strongly stabilizes the system in the neutral configuration with the system rotating at the given constant angular velocity View full abstract»

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  • Scheduling with asynchronous service opportunities with applications to multiple satellite systems

    Publication Year: 1993 , Page(s): 1820 - 1833
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (944 KB)  

    A single server is assigned to M parallel queues with independent Poisson arrivals. Service times are constant, but the server has the opportunity to initiate service at a given queue only at times forming a Poisson process. Four related scheduling policies are investigated: a simple first-come, first-serve policy for which the stability region is determined: a policy with maximum throughput, but requiring the server to have advance knowledge of service opportunities; a policy of threshold type, which is shown to be optimal among nonlookahead policies with preemption; and an adaptive policy, which when M=2 is shown to provide stability for all arrival rate vectors for which stability is possible under any nonlookahead policy with preemption. The work is motivated by the problem of transmission scheduling for a packet-switched, low-altitude, multiple-satellite system View full abstract»

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  • Optimal control of the M/G/1 queue with repeated vacations of the server

    Publication Year: 1993 , Page(s): 1766 - 1775
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (572 KB)  

    An M/G/1 queue where the server may take repeated vacations is considered. Whenever a busy period terminates, the server takes a vacation of random duration. At the end of each vacation, the server may either take a new vacation or resume service; if the queue is found empty, the server always takes a new vacation. The cost structure includes a holding cost per unit of time and per customer in the system and a cost each time the server is turned on. One discounted cost criterion and two average cost criteria are investigated. It is shown that the vacation policy that minimizes the discounted cost criterion over all policies (randomized, history dependent, etc.) converges to a threshold policy as the discount factor goes to zero. This result relies on a nonstandard use of the value iteration algorithm of dynamic programming and is used to prove that both average cost problems are minimized by a threshold policy View full abstract»

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  • Model reference adaptive control of time varying and stochastic systems

    Publication Year: 1993 , Page(s): 1738 - 1753
    Cited by:  Papers (19)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (820 KB)  

    The adaptive control of general delay, linear time-varying systems is addressed. A simple model reference adaptive control law is devised. It does not require a priori knowledge of the sign of the high-frequency gain. This control law coupled with the parameter estimation equations allows a simple representation of the closed-loop system. This greatly eases the stability and performance analysis, and has potential for generalization to adaptive pole placement and other control laws suitable for nonminimum-phase systems. For the Kalman filter parameter estimator coupled with this control law, stability is obtained without persistence of excitation or knowledge of the sign of the high frequency gain. Performance results for the extended-least-squares algorithm are described View full abstract»

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  • Control of discrete event systems modeled as hierarchical state machines

    Publication Year: 1993 , Page(s): 1803 - 1819
    Cited by:  Papers (29)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1132 KB)  

    Discrete-event systems (DESs) are systems in which state changes take place in response to events that occur discretely, asynchronously, and often nondeterministically. A class of DESs modeled as hierarchical state machines (HSMs), a special case of the statecharts formalism introduced recently, is considered. An efficient algorithm is provided for solving reachability problems in the HSM framework. It utilizes the hierarchical structure of HSMs. This efficient solution is used extensively in control applications, where controllers achieving a desired behavior are synthesized online View full abstract»

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  • Some results on minimum magnitude regulated response

    Publication Year: 1993 , Page(s): 1862 - 1866
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (320 KB)  

    Analytical results are obtained for the minimum peak tracking error magnitude achievable by some finite settling time control systems in response to a step reference input. The limits of these results as the settling time approaches infinity are also obtained. These represent performance bounds which apply for any finite order linear time-invariant (LTI) controller of a given configuration (i.e., one-parameter or two-parameter). The systems considered are one-parameter discrete-time single-input, single-output (SISO) where the plant has one unstable pole and one non-minimum-phase zero. The result for a two-parameter compensator for plants with one non-minimum-phase zero is presented 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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Editor-in-Chief
P. J. Antsaklis
Dept. Electrical Engineering
University of Notre Dame