Keylan Alimhan

Robust practical output tracking by output compensator for a class of uncertain inherently non-linear systems

This paper studies the robust practical output tracking problem using a dynamic output feedback controller (called an output compensator) for a family of uncertain inherently non-linear systems in the p-normal form of a particularly complex nature such that their linearisation around the equilibrium state may be unstabilisable and/or undetectable. It is shown that under some mild conditions on such a given system, it is possible to construct an output compensator achieving the robust practical output tracking and such a compensator is explicitly constructed by the coupled controller-observer design methods recently proposed. The usefulness of the result obtained is illustrated by a simple numerical example.

A new result on practically output tracking control of nonlinear systems that may not be linearizable at the origin

This paper studies a globally practical output-tracking control of inherently nonlinear systems, whose chained integrator part has the power of positive odd rational numbers. Since the power is not restricted to be larger than or equal to one, the linearization of the system at the origin may fail. Nevertheless, it is proved that, under mild assumptions, globally practical output-tracking is achievable by state feedback controller.

Locally Asymptotically Stable Fixed-point Assignment Problems in Neural Networks and Application to Associative Memory

This paper proposes and studies in the frame work of systems and control theory the problem of how to construct a dynamical system defined over a Hilbert space such a way that any given vectors are assigned to locally asymptotically stable fixed-points of the system. Some basic properties of such systems are investigated, and further the results are applied to neural networks to implement associative memory or pattern recognition for two-dimensional images in such a way that a certain structural deformation of images is acceptable. Finally some numerical examples for associative memory are presented to illustrate the performance.

Global stabilization of a class of uncertain nonlinear systems using output feedback

This paper studies the global stabilization by output feedback for uncertain nonlinear systems whose dynamic may not exactly known but satisfies some relaxed triangular-type conditions. Using a feedback domination design method, we explicitly construct a dynamic output compensator, which globally stabilizes such an uncertain nonlinear system. The usefulness of our result is illustrated as an example.

Global Stabilization of Feedback Non-Linearizable Nonlinear Systems without Strict Triangular Condition

This paper studies a global stabilization problem for a class of high-order nonlinear systems in a cascaded chain form. The high-order cascade systems considered in this paper are feedback non-linearizable and non-affine in the control variables without the strict triangular condition, and therefore this global stabilization problem cannot be directly handled by any existing method. It is shown that under some suitable assumptions on such a nonlinear system the global stabilization problem is solvable and a globally stabilizing smooth state feedback controller can be recursively constructed, using the so-called adding one power integrator technique recently proposed by Lin and Qian (Systems and Control Letters, vol. 39 (2000), pp. 339-351) together with the back-stepping technique. A simple numerical example is worked out to demonstrate the effectiveness of the proposed controllers.

Output Tracking Problem of Uncertain Nonlinear Systems with High-Order Nonlinearities

This study addresses the problem of global practical output tracking by state feedback for a class of high-order non-linear systems with more general uncertainties, to which the existing control methods are inapplicable. By introducing sign function and necessarily modifying the method of adding a power integrator, a continuous state feedback controller is successfully constructed to guarantee the tracking error achieve arbitrarily small.

Global Practical Output Tracking of Inherently Nonlinear Systems Using Continuously Differentiable Controllers

This paper considers the global practical output tracking problem by at least continuously differentiable () state feedback for a class of uncertain nonlinear systems whose linearization around the origin may contain uncontrollable modes. Based on utilizing the homogeneous domination approach, we not only propose conditions of constructing a global continuously differentiable () controller, but also provide explicit design schemes for such systems. Finally, a numerical example demonstrates the effectiveness of the result.

Methods for applying VAD in Kazakh speech recognition systems

This article considers the algorithm “Voice activity detection” and the using VAD algorithm in the system of Kazakh speech recognition. The paper presents a mathematical model VAD and methods for detecting voice data: pauses between sentences, words, individual sounds. VAD algorithm is adapted to the recognition of Kazakh speech counting the basic properties of Kazakh language. Voice activity detection researches in Kazakh speech are being conducted for the first time. The results of the spectral analysis are displayed on the picture.

Associative Memory for Noisy and Structurally Deformed Two-Dimensional Images Using Neural Networks

This paper studies the problem of understanding noisy and structurally deformed two-dimensional images by means of abstractly defined neural works. First, in the framework of systems theory a neural network defined over a Hilbert space is introduced such that any given vectors in the Hilbert space are assigned to locally asymptotically stable fixed points of the network. Then, introducing structural deformation into images a modified neural network is constructed to remove such structural deformation as well as noise. Finally, the modified neural network is used for implementing associative memory of two-dimensional images corrupted by structural deformation as well as noise, and some numerical examples are presented to illustrate the result.

Robust Global Practical Output Tracking of Uncertain Nonlinear Systems by Smooth Output Feedback

This paper considers a robust global practical output tracking problem for a family of uncertain nonlinear systems with uncontrollable and unobservable linearization. It is shown that under some mild conditions on such a system there is a smooth output feedback achieving global practical output tracking and such a smooth output controller is explicitly constructed by a new design method proposed. The design of smooth output feedback controllers does not require the precise information of the uncertain system and depends only on the knowledge of the bounding system. The usefulness of our result is illustrated by a numerical example.