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Automatic Control, IEEE Transactions on

Issue 4 • Date August 1967

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Displaying Results 1 - 25 of 49
  • [Front cover and table of contents]

    Publication Year: 1967 , Page(s): 0
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    Freely Available from IEEE
  • Save the JACC!

    Publication Year: 1967 , Page(s): 349 - 350
    Cited by:  Papers (1)
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    Freely Available from IEEE
  • Issue in brief

    Publication Year: 1967 , Page(s): 351 - 352
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    Freely Available from IEEE
  • Simplified processing of star tracker commands for satellite attitude control

    Publication Year: 1967 , Page(s): 353 - 359
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (644 KB)  

    A method for using gimbaled star trackers to obtain useful attitude control signals is presented. Gimbaled trackers are required if the spacecraft is to be pointed in an arbitrary direction and if any suitable star is to be chosen as a guide star for the star tracker. With the trackers locked onto their guide stars, deviation of the gimbals from their commanded angles provides a measure of the error in vehicle attitude. Since the errors are generated about axes which are not necessarily mutually orthogonal nor aligned with the spacecraft's control axes, they must be processed somehow to make them useful as control signals. The study considered here develops a realizable approximation of the nonlinear processor required to generate vehicle attitude errors from the gimbal angle error measurements. The approximate processor is simple enough for use on board current spacecraft and allows satisfactory performance over as wide a range of star tracker gimbal angles and satellite attitudes as desired. View full abstract»

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  • Design of a digital controller for a tracking telescope

    Publication Year: 1967 , Page(s): 359 - 367
    Cited by:  Papers (1)  |  Patents (1)
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    This paper discusses the application of certain aspects of modern control theory to the design of a large tracking telescope that is digitally controlled. Two of the most important criteria are tracking accuracy and response time. The system is also constrained by saturation effects on the control variable. State-transition techniques which have finite settling times over a broad class of inputs are used in conjunction with a suitable inequality condition to obtain a control with near minimum time response. Digital simulation has shown that the design obtained has high accuracy and does not exceed the saturation limitation on the control variable. View full abstract»

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  • A time-optimal adaptive control system via adaptive switching hypersurface

    Publication Year: 1967 , Page(s): 367 - 373
    Cited by:  Papers (1)
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    This paper presents a technique for synthesizing a time-optimal adaptive control system. The technique consists of combining off-line memorization with simple on-line calculations to determine the control signal. The adaptive switching hypersurface consists of images of switching points of each plant in the extended state space (the present and past state variables). The approximation is obtained by linearizing the projection of the adaptive switching hypersurface in a subspace, and finally storing the parameters of the hyperplanes thus obtained in memory. The on-line calculation corresponds to a simple function generator. The function generator consists of the memory containing the values of parameters of the hyperplanes and a linear interpolator. The input of the function generator is the present and past state variables, and its final output is +K or -K . The technique is applied to the pitch axis adaptive regulator control of the F-101B aircraft in various flight conditions, and simulations of the system by the hybrid computer are obtained. View full abstract»

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  • Design of approximately optimal feedback controllers for systems with bounded states

    Publication Year: 1967 , Page(s): 373 - 379
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (552 KB)  

    Implementation is one of the most pronounced difficulties in designing optimal feedback controllers to prevent the state variables of the system from exceeding predetermined bounds. A method to obtain approximately optimal feedback controllers based on the geometric features of the optimal open-loop solution of the bounded state variable problem is presented in this paper. Easily instrumentable controllers are designed and successfully tested on various plants to furnish a value of the performance criterion close to the optimal. Typical examples illustrate the approach. View full abstract»

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  • Design of piecewise-linear switching functions for relay control systems

    Publication Year: 1967 , Page(s): 380 - 387
    Cited by:  Papers (2)
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    The design of piecewise-linear switching functions is investigated for linear, constant, lumped systems with a single ideal relay controller with respect to a transient response (minimum-time) performance criterion. A design method is presented which consists of a series of steps leading finally to the optimization of parameters by a gradient or other search technique suitable for computer implementation. The preliminary steps are devoted to reducing the dimensionality of the parameter space which must be searched, defining the criterion function so as to yield a surface which is reasonably smooth and free of relative minima, and insuring that the search is started with a feasible parameter set. It is concluded that easily implemented piecewise-linear switching functions can be designed so as to yield improved performance, both in terms of settling times and region of stability in the state space, over that attainable with linear switching functions. The complexities of the performance surface are such, however, that it is felt that frequently the determination of a switching function by the heuristic guides described, constitutes an adequate design without the refinement of parameter optimization. View full abstract»

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  • An interior penalty method for inequality constrained optimal control problems

    Publication Year: 1967 , Page(s): 388 - 395
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (625 KB)  

    This paper presents a penalty function approach to the solution of inequality constrained optimal control problems. The method begins with a point interior to the constraint set and approaches the optimum from within, by solving a sequence of problems with only terminal conditions as constraints. Thus, all intermediate solutions satisfy the inequality constraints. Conditions are given which guarantee that the un "constrained" problems have solutions interior to the constraint set and that in the limit these solutions converge to the constrained optimum. For linear systems with convex objective and concave inequalities, the unconstrained problems have the property that any local minimum is global. Further, under these conditions, upper and lower bounds in the optimum are easily available. Three test problems are solved and the results presented. View full abstract»

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  • A game theoretic approach to optimal control in the presence of uncertainty

    Publication Year: 1967 , Page(s): 395 - 401
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (548 KB)  

    The optimal control problem, in the presence of uncertainty in the plant, is formulated as a game between the uncertainty and the control variables. This approach gives an optimal control strategy which is effective even under the "worst" conditions of uncertainty. The optimal control of a second-order plant with uncertainty in frequency brings out several interesting features. In particular, the existence of a barrier demarcating the controllable and uncontrollable regions in the phase plane is revealed, which is absent in the corresponding one-sided optimization. View full abstract»

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  • Controlability and observability of composite systems

    Publication Year: 1967 , Page(s): 402 - 409
    Cited by:  Papers (31)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (697 KB)  

    This paper studies the controllability and observability of the parallel and the tandem connection of two linear time-invariant differential systems; it uses the Jordan form representation; it does not assume that the eigenvalues of each representation are simple nor that the two sets of the eigenvalues are disjoint. The controllability and observability of the composite representations require only testing the linear independence of some constant vectors. Some sufficient conditions require just the transfer function matrices. View full abstract»

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  • An algebraic solution to the spectral factorization problem

    Publication Year: 1967 , Page(s): 410 - 414
    Cited by:  Papers (49)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (422 KB)  

    The problem of giving a spectral factorization of a class of matrices arising in Wiener filtering theory and network synthesis is tackled via an algebraic procedure. A quadratic matrix equation involving only constant matrices is shown to possess solutions which directly define a solution to the spectral factorization problem. A spectral factor with a stable inverse is defined by that unique solution to the quadratic equation which also satisfies a certain eigenvalue inequality. Solution of the quadratic matrix equation and incorporation of the eigenvalue inequality constraint are made possible through determination of a transformation which reduces to Jordan form a matrix formed from the coefficient matrices of the quadratic equation. View full abstract»

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  • A nonlinear discrete system equivalence of integral pulse frequency modulation systems

    Publication Year: 1967 , Page(s): 415 - 422
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (586 KB)  

    In this paper a study of the effect of integral pulse frequency modulation (IPFM) on single-input single-output feedback control is attempted. For zero input such systems can be reduced to a nonlinear discrete system. Lagrange stability concepts are used for the stability study of such systems. A step-by-step procedure is devised for the construction of the state trajectories of the IPFM system. This has been applied to a second-order plant where it is shown that instability, asymptotic stability in the large, and asymptotic stability in the Lagrange sense are exhibited by such systems. It is also shown that in IPFM systems, the periodic oscillation that exists depends on the initial state. The equivalence concepts of such systems are reviewed critically, and the limitations of the method are pointed out. Further research in this area of feedback modulation is proposed and discussed. View full abstract»

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  • Bounded-input bounded-output stability of nonlinear time-varying discrete control systems

    Publication Year: 1967 , Page(s): 423 - 427
    Cited by:  Papers (3)
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    It is shown that a discrete control system is bounded-input bounded-output (BIBO) stable if and only if there exist Liapunov functions possessing certain properties. As an illustration, a frequency criterion is developed for the BIBO stability of a class of non-linear discrete systems. View full abstract»

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  • Kalman-Bucy filter for optimum radio-inertial navigation

    Publication Year: 1967 , Page(s): 430 - 431
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    A seemingly paradoxical situation existed in the Kalman-Bucy formulation of a problem of optimum radio-inertial navigation. The difficulty is traced to the a priori information used in the estimate and variance equations. The reason for the existence of an improved a priori estimate is given. It is shown that with the improved a priori information as initial conditions, the Kalman-Bucy filter gives the same result as that obtained by Peterson originally using the integral equation approach. View full abstract»

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  • Estimation of the state vector of a linear stochastic system with a constrained estimator

    Publication Year: 1967 , Page(s): 432 - 433
    Cited by:  Papers (29)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (246 KB)  

    The paper presents a constructive design procedure for the problem of estimating the state vector of a discrete-time linear stochastic system with time-invariant dynamics when certain constraints are imposed on the number of memory elements of the estimator. The estimator reconstructs the state vector exactly for deterministic systems while the steady-state performance in the stochastic case may be comparable to that obtained by the optimal (unconstrained) Wiener-Kalman filter. View full abstract»

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  • Linear time-lag systems with side constraints

    Publication Year: 1967 , Page(s): 434 - 435
    Cited by:  Papers (2)
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    Necessary and sufficient conditions for an optimal control for linear time-lag optimal control systems with side constraints are given. Also the existence of an optimal control is proved. View full abstract»

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  • On the general functional matrix for a linear system

    Publication Year: 1967 , Page(s): 436 - 438
    Cited by:  Papers (3)
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    Macfarlane [1] has shown that for any asymptotically stable linear system with constant coefficients there exists a general functional matrix that can be used to evaluate a very wide class of system functionals. A disadvantage is that the algebra needed to determine this matrix, while straightforward, is lengthy and tedious. It is shown that the general functional matrix can be obtained by a completely systematic procedure that involves little or no algebraic manipulation. The relationship with some recent work by Bass and Webber [4] on optimal linear systems with quartic and higher-order performance criteria is investigated, and a method based on the solution of the Liapunov matrix equation is suggested for obtaining the optimal nonlinear feedback control. An explicit form for the inverse of a related Kronecker sum is also given. View full abstract»

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  • Identification and control of linear discrete systems

    Publication Year: 1967 , Page(s): 438 - 442
    Cited by:  Papers (20)
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    Real-time identification and control of linear discrete systems with Gauss-Markov random parameters and conditioned quadratic cost function are considered. Algorithms for explicit calculation of the identification and control are given for systems with perfect state measurement and are illustrated by example applications. The control strategy generated by the cost function is an identitication-adaptive controller which is continually revised as new data are received. The identification equations develop an explicit model of the system which is available for other purposes if desired, and can be used apart from the control context. View full abstract»

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  • Finding the stability and sensitivity of large sampled systems

    Publication Year: 1967 , Page(s): 442 - 445
    Cited by:  Papers (1)
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    The stability of a large sampled system is examined by finding the eigenvalues of the difference equation that describes the system. The derivatives of these eigenvalues with respect to the system parameters are found to give the sensitivity of the system to the various parameters. A method of finding the difference equations for the system is described which is based on exponentiating the matrix of the system with the samplers open. The problem of multiple eigenvalues is considered, and a block-form solution is used to determine the nature of the multiplicity of the multiple eigenvalues. View full abstract»

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  • Some aspects of the Lur'e problem

    Publication Year: 1967 , Page(s): 451 - 453
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (287 KB)  

    The problem of absolute stability of feedback systems containing a single nonlinearity is considered for the case of the linear transfer function having an equal number of finite poles and zeros. Explicit Liapunov functions are presented and frequency-domain criteria are derived for systems for which the nonlinear function f(\cdot) belongs to the class A_{\infty } ( f lies in the first and thirdquadrants) or its subclasses such as monotonically increasing functions (\finM_{\infty }) , odd-monotonic functions (\fino_{\infty }) , and functions witha power-law restriction (\finP_{\infty }) . A new class of functions with restricted asymmetry having the property |{f(\theta)/f(-0)}, \leq c for all \theta (\theta\neq0) is introduced, and the results obtained can be used to establish stability in some cases even when the Nyquist plot of the linear part transfer function lies in all the four quadrants and the nonlinearity is not necessarily odd. Restrictions on the derivative of the non-linearity have been taken into account by means of a transformation, and the resulting stability criterion is seen to be an improvement over those obtained in some earlier papers. View full abstract»

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  • A graphical method for calculation of transfer functions

    Publication Year: 1967 , Page(s): 454 - 455
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  • A switching policy for predictive control systems

    Publication Year: 1967 , Page(s): 455 - 456
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  • Some comments on "Extremum control of continuous systems"

    Publication Year: 1967 , Page(s): 456 - 457
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  • On a decomposition technique for multilevel control systems

    Publication Year: 1967 , Page(s): 457 - 458
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    First Page of the Article
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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