No description available.

Thesis (M.S.)--Rochester Institute of Technology, 1992. / Typescript. Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2002. / Vita. Includes bibliographical references. Available also from UMI Company.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 77-79). Also available via the Internet.

It is assumed that processes to be identified or controlled can be described by linear or non-linear differential equations with unknown coefficients aᵢ. For on-line identifications a model is constructed to have the same form of differential equation as the process, but with adjustable parameters αᵢ replacing the aᵢ. The parameters αᵢ are adjusted in a steepest descent fashion; they are shown to converge to the aᵢ as long as an adjustment gain K(t) is non-negative, and not identically zero. An approximate analysis is carried out to determine the best constant K which gives the fastest identification. Optimal control theory is introduced to find the best piecewise continuous K(t) in the interval 0 ≤ K(t) ≤ Kmax . From the exact solution in a special case, a switched suboptimal K which always gives fast identification is determined. Identification schemes are developed for processes which include an unknown non-linearity that, can be assumed to be piecewise linear. An adaptive control, system is developed to control processes with unknown time-varying coefficients. The system is shown to be stable as long as the process inverse is stable; the process need not be stable. Systems to control linear and non-linear unstable processes are designed and simulated. The limitations of the adaptive system are determined, and compared with the limitations of conventional feedback systems. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

Sufficient conditions for the absolute stability of a class of nonlinear sampled-data systems are derived using the techniques of system transformations due to Aizerman and Gantmacher. These criteria are based on different forms used to approximate the area under the nonlinear characteristic. It is also shown that the stability criterion can be improved by relaxing a restriction on the slope of nonlinear element. In multiple nonlinearily continuous systems, by the application of numerical techniques, it was shown that some improvement over previous stability bounds can be made. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

This thesis is in two parts, both considering the absolute stability of nonlinear systems. In the first two chapters the stability of certain classes of nonlinear time invariant systems involving several nonlinearities is considered. A number of graphical methods are given for testing the stability of these systems. The graphical tests are equivalent to a weakened form of the Popov criterion. The third chapter derives a stability condition for nonlinear systems involving a linear time-varying gain. The time-varying gain is assumed to satisfy conditions on its magnitude and rate of change. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

No description available.

Thesis--Virginia Polytechnic Institute and State University, 1978. / Also available via the Internet.

Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references (leaves 218-224). Available also in a digital version from Dissertation Abstracts.