Encontrados 15 documentos, a visualizar página 1 de 2
Averaging methods for design of spacecraft hysteresis damper
Smirnov, Georgi; Gama, Ricardo; Guerman, Anna D.; Seabra, AnaThis work deals with averaging methods for dynamics of attitude stabilization systems. The operation of passive gravity-gradient attitude stabilization systems involving hysteresis rods is described by discontinuous differential equations. We apply recently developed averaging techniques for discontinuous system in order to simplify its analysis and to perform parameter optimization. The results obtained using ...
Attitude dynamics and stability of a simple solar photon thruster
Guerman, Anna; Smirnov, Georgi; Pereira, Maria CeciliaThis paper is dedicated to the development of a model of the attitude dynamics for a nonideal Simple Solar Photon Thruster (SSPT) and to the analysis of sailcraft motions with respect to their centre of mass. Derivation of the expressions for force and torque due to solar radiation that is valid for the case, when there is a misalignment of the SSPT axis with the sun direction, is followed by study of sailcraft...
Numerical approaches in a problem of management of hydroelectric resources
Bushenkov, V. A.; Ferreira, M. M. A.; Ribeiro, A. F.; Smirnov, GeorgiIn this paper we consider a simpli ed model for a system of hydro-electric power stations with reversible turbines. The objective of our work is to obtain the optimal pro t of power production satisfying restric- tions on the water level in the reservoirs. Two di erent numerical approaches are applied and compared. These approaches centers on a global optimization technique (Chen-Burer algorithm) and on a Proje...
On the Newton method for set-valued maps
Dias, Susana; Smirnov, GeorgiThe Newton method is one of the most powerful tools used to solve systems of nonlinear equations. Its set-valued generalization, considered in this work, allows one to solve also nonlinear equations with geometric constraints and systems of inequalities in a unified manner. The emphasis is given to systems of linear inequalities. The study of the wellposedness of the algorithm and of its convergence is fulfille...
Closed relative trajectories for formation flying with single-input control
Guerman, Anna; Ovchinnikov, Michael; Smirnov, Georgi; Trofimov, SergeyEm publicação. ; We study the problem of formation shape control under the constraints on the thrust direction. Formations composed of small satellites are usually subject to serious limitations for power consumption, mass and volume of the Attitude and Orbit Control System (AOCS). If the purpose of the formation flying mission does not require precise tracking of a given relative trajectory, AOCS of satellit...
Weak exponential stability for time-periodic differential inclusions via first ...
Gama, Ricardo; Smirnov, GeorgiPublished online: 20 June 2012 ; In this work we propose a method to study a weak exponential stability for time-varying differential inclusions applying an averaging procedure to a first approximation. Namely, we show that a weak exponential stability of the averaged first approximation to the differential inclusion implies the weak exponential stability of the original time-varying inclusion. The result is i...
On the optimal control of a cascade of hydro-electric power stations
Ribeiro, A. F.; Guedes, M. C. M.; Vilela, S.; Smirnov, GeorgiIn this paper we consider a model for a cascade of hydroelectric power stations where some of the stations have reversible turbines. The objective of our work is to optimize the profit of power production satisfying restrictions on the water level in the reservoirs. The problem is considered in the framework of discretetime optimal control and is solved using numerical methods. The optimization uses real data o...
On the evaluation of a public transportation network quality : criteria validat...
Guedes, M. C. M.; Oliveira, Natália; Santiago, Sérgio; Smirnov, GeorgiA public transportation network serves in adequate way a population if it evolves in time following the existent social reality. Changes made in order to improve service must be analyzed and evaluated. The introduction of modern technology to validate the fare card allowed a quick access to important, although incomplete, data. A data basis with the validation information can be used to construct an origin-dest...
Orbital manoeuvres with single-input control
Guerman, Anna; Smirnov, GeorgiWe study the problem of orbital control under the constraints on the thrust direction for a nonlinear dynamical model. The satellite is equipped with a passive attitude control system providing one-axis stabilization and a propulsion system consisting of one or two thrusters oriented along the stabilized axis. Different applications, such as formation flying and satellite de-orbiting are considered.
Parameter optimization for stabilizers
Guerman, Anna; Seabra, Ana M.; Smirnov, GeorgiThe aim of this work is to develop an effective numerical tool oriented to optimization of stabilizer parameters according to different criteria that appear in engineering practice. We formulate a special optimization problem that allows us to determine optimal parameters of a stabilizer. The obtained results are applied to choose parameters of a spacecraft stabilization system. We discuss the choice of optimiz...
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