DOI: https://doi.org/10.32515/2414-3820.2018.48.35-44

The Problem of Selection of the Optimal Strategy of Minimax Control by Objects in Agricultural Production with Distributed Parameters

Oleksiy Lobok, Boris Goncharenko, Larisa Vihrova, Marina Sych

About the Authors

Oleksiy Lobok, Associate Professor, Doctor of Physical and Mathematical Sciences, National University of Food Technologies, Kyiv, Ukraine

Boris Goncharenko, Professor, Doctor in Technics (Doctor of Technics Sciences), National University of Food Technologies, Kyiv, Ukraine, e-mail: goncharenkobn@i.ua

Larisa Vihrova, Professor, PhD in Technics (Candidate of Technics Sciences), Central Ukrainian National Technical University, Kropyvnytskyi, Ukraine, e-mail: vihrovalg@ukr.net

Marina Sych, PhD in Technics (Candidate of Technics Sciences), National University of Bioresources and Nature Management of Ukraine, Kyiv, Ukraine, e-mail: sm.nuft@gmail.com

Abstract

Тhe problem of minimax control synthesis for objects in agricultural production that are described by a two-dimensional heat conduction equation of parabolic type is solved. It is assumed that the control object functions under uncertainty conditions, and the perturbations acting on the object belong to some given hyperelipsoid. The problem of constructing a regulator in the state of an object for cases of point and mobile limit control is considered in accordance with the integral-quadratic quality criterion. With the help of numerical optimization methods, the problem of determining the optimal location of concentrated regulators at the boundary of a rectangular region and the problem of finding the optimal law of motion of a mobile limit regulator is solved. The problem is posed and solved in the minimax formulation when there is an optimal control on the state of the object functioning under uncertainty conditions so that the regulator minimizes the maximum control error from a set of possible values, taking into account the most unfavorable perturbations that can act on the object or system. In this case, the perturbations of the object belong to a given limited region. The results of computational experiments illustrating the effectiveness of the constructed limiting concentrated and moving regulators are presented. The obtained results indicate that the controls found in the work are indeed optimal and ensure minimum errors (deviations from the given state) of the functioning of the system and energy costs for the implementation of control under given conditions and in the absence of any information on external action other than the region of permissible perturbations. In the work, for the first time, a minimax approach was used to control the objects described by the two-dimensional parabolic type thermal conductivity equation; the theoretical positions of synthesis of minimax regulators for cases of lumped boundary (point) and moving regulators are considered; algorithmic software is developed that allows to simulate the dynamics of the constructed minimax-regulators and to investigate the corresponding transients.

Keywords

minimax control, regulators, distributed parameter systems, optimization, gradient projection method, point and mobile limit controls

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References

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