By Topic

Automatic Control, IEEE Transactions on

Issue 10 • Date Oct. 1991

Filter Results

Displaying Results 1 - 15 of 15
  • Comments on "On adaptive inverse dynamics control of rigid robots" [with reply]

    Page(s): 1215 - 1216
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (130 KB)  

    The commenters point out an error in the adaptive control approach for robotic manipulators given in the above-named work by M.W. Spong and R. Ortega (see ibid., vol.35, p.92-5, Jan. 1990). It is noted that the authors assert that their adaptive control scheme eliminates the restriction given in J.J. Craig (1986) on the estimated inertia matrix; however, the commenters point out that a form of the inverse of the estimated inertia matrix must be bounded for the acceleration to be bounded. In a reply, the authors acknowledge the error in their paper.<> View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Doubly coprime matrix-fraction representations using proportional and derivative feedback concepts in generalized state-space systems

    Page(s): 1193 - 1195
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (240 KB)  

    The concepts of proportional and derivative state feedback are used to derive some explicit formulas for doubly coprime matrix-fraction representations of generalized state-space systems. Specifically, proportional and derivative state feedback is used to determine the doubly coprime matrix-fraction representations and to solve the corresponding generalized Bezout identity in polynomial matrix form View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Feedforward digital tracking controller

    Page(s): 1199 - 1120
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (364 KB)  

    A digital tracking controller for linear time invariant control systems is presented which is based on feeding forward the reference input and its delayed values. A necessary and sufficient condition for the existence of the proposed controller is also given. The choice between the proposed feedforward tracking controller and one based on error integral augmentation depends on the characteristics and requirements of the system under consideration. In certain cases, a better result can be achieved by using a combination of the two methods View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Asymptotic stabilization of minimum phase nonlinear systems

    Page(s): 1122 - 1137
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1380 KB)  

    How a class of multivariable nonlinear systems can be stabilized about an equilibrium via smooth state feedback is shown. More precisely, conditions under which, for every compact set of initial states, it is possible to design a feedback law which drives to the equilibrium all initial states in this compact set are described. The theory includes the development of globally defined transformations of the system equations to their global normal form View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • H controller design for the SISO case using a Wiener approach

    Page(s): 1204 - 1208
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (392 KB)  

    A solution to the H mixed sensitivity problem for the SISO (single-input single-output) case is obtained using a Wiener approach to parameterize all equalizing and stabilizing controllers. The controller which incorporates the LQG (linear quadratic Gaussian) solution has a structure similar to that of D.C. Youla et al. (1976). The system of equations thus obtained is square and has some degree of advantage over previous solutions View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The necessity of the small-gain theorem for time-varying and nonlinear systems

    Page(s): 1138 - 1147
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (672 KB)  

    It is shown that an appropriately modified version of the small-gain theorem which uses the `asymptotic gain' of a fading-memory system leads to a necessary and sufficient condition for the stable invertibility of certain feedback operators. This modified small-gain theorem is then used to obtain conditions for robust finite-energy input-output stability of: (1) nonlinear plants subject to nonlinear time-varying perturbations; and (2) linear time-varying plants subject to linear time-varying perturbations. These conditions are shown to be necessary as well as sufficient View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Piecewise monotone filtering in discrete-time with small observation noise

    Page(s): 1181 - 1186
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (500 KB)  

    A discrete-time model for filtering with small observation noise is considered. A piecewise linear observation function is considered with two intervals of monotonicity. A sequential quadratic variation test is found to detect intervals of linearity of the observation function. Diffusion approximations to certain discrete processes are made to estimate the mean times for reaching a decision and the error probabilities View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A simple PD controller for robots with elastic joints

    Page(s): 1208 - 1213
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (440 KB)  

    The point-to-point control of manipulators having elastic joints is considered. It is shown that a simple PD (proportional plus derivative) controller, similar to that used for rigid robots, suffices to globally stabilize the elastic joint robots about a reference position. A robustness analysis is also given with respect to uncertainties on the robot parameters. The results of numerical simulation tests of a manipulator with three revolute elastic joints are presented View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Efficient DFT-based model reduction for continuous systems

    Page(s): 1188 - 1193
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (548 KB)  

    A method for online identification of reduced-order models (ROM) of stable continuous systems is presented. The method is unique because it utilizes the moving discrete Fourier transform (MDFT) to continuously monitor the frequency-domain profile of the plant input and output signals. These signals need not be sinusoidal, although they must be accurately represented by their DFTs. Also, the input must contain at least n frequency components (for an nth-order ROM). A computer simulation demonstrates the method View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • On the estimation of two-dimensional moving average parameters

    Page(s): 1196 - 1199
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (284 KB)  

    The authors address the estimation problem of moving average (MA) parameters of a 2D autoregressive moving average (ARMA) model. The problem is equivalent to solving a set of overdetermined 2D transcendental equations. Based on some extensions of the Newton-Raphson method, an iterative algorithm is proposed for estimating 2D MA parameters. The performance of the algorithm is demonstrated by a numerical example. For 2D sinusoids in white noise spatial series, some interesting features of 2D ARMA modeling are observed View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The attitude control problem

    Page(s): 1148 - 1162
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1240 KB)  

    A general framework for the analysis of the attitude tracking control problem for a rigid body is presented. A large family of globally stable control laws is obtained by using the globally nonsingular unit quaternion representation in a Lyapunov function candidate whose form is motivated by the consideration of the total energy of the rigid body. The controllers share the common structure of a proportional-derivative feedback plus some feedforward which can be zero (the model-independent case), the Coriolis torque compensation, or an adaptive compensation. These controller structures are compared in terms of the requirement on the a priori model information, guaranteed transient performance, and robustness. The global stability of the Luh-Walker-Paul robot end-effector controller is also analyzed in this framework View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Direct position plus velocity feedback control of large flexible space structures

    Page(s): 1186 - 1188
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (296 KB)  

    The authors demonstrate the feasibility of shape and position control of large flexible structures with collocated sensors and actuators using direct position-plus-velocity feedback. This result is important for large space structures where the number of modes is very large and eventually unknown. When the number of inputs equals the number of outputs, the stabilizing feedback gain stands for any positive definite matrix, including diagonal matrices. This result may explain the success of decentralized adaptive controllers when a reasonable number of sensors is used to satisfy the observability assumption View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Lyapunov design of stabilizing controllers for cascaded systems

    Page(s): 1177 - 1181
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (368 KB)  

    The design of a state feedback law for an affine nonlinear system to render a (as small as possible) compact neighborhood of the equilibrium of interest globally attractive is discussed. Following Z. Artstein's theorem (1983), the problem can be solved by designing a so-called control Lyapunov function. For systems which are in a cascade form, a Lyapunov function meeting Artstein's conditions is designed, assuming the knowledge of a control law stabilizing the equilibrium of the head nonlinear subsystem. In particular, for planar systems, this gives sufficient and necessary conditions for a compact neighborhood of the equilibrium to be stabilized View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Parameter estimation for linear discrete-time models with random coefficients

    Page(s): 1213 - 1215
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (232 KB)  

    The problem of parameter estimation in linear discrete-time systems with random coefficients is discussed. In particular, the maximum-likelihood estimators and their consistency for the defined structure of the model are derived. The estimators have a structure similar to that of the least square estimators for the linear discrete-time system with constant coefficients View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Control oriented system identification: a worst-case/deterministic approach in H

    Page(s): 1163 - 1176
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1192 KB)  

    The authors formulate and solve two related control-oriented system identification problems for stable linear shift-invariant distributed parameter plants. In each of these problems the assumed a priori information is minimal, consisting only of a lower bound on the relative stability of the plant, an upper bound on a certain gain associated with the plant, and an upper bound on the noise level. The first of these problems involves identification of a point sample of the plant frequency response from a noisy, finite, output time series obtained in response to an applied sinusoidal input with frequency corresponding to the frequency point of interest. This problem leads naturally to the second problem, which involves identification of the plant transfer function in H from a finite number of noisy point samples of the plant frequency response. Concrete plans for identification algorithms are provided for each of these two problems View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.

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

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
P. J. Antsaklis
Dept. Electrical Engineering
University of Notre Dame