I. N. Krutova

Studying Stability of the Flexible Spacecraft with a Discrete Control System

Stability of the spacecraft was considered with regard for its elastic structural oscillations arising under discrete control. The control signal is a discrete process which is both stochastic and regular. Stability was studied by passing to a discrete mathematical model of the system and applying an approach based on the discrete counterparts of the Lyapunov theorems.

Fuzzy Logic-based Adaptive Control System for In-orbit Assembly of Large Space Structures

Design of a fuzzy adaptive algorithm to control orientation of a large space structure during the progress of in-orbit assembly was considered. For the discretely evolving structure, a matrix description of the set of modal-physical models was given. Introduced were the functions of influence of the basic control on the dynamics of the autonomous models of isolated flexible modes that underlie the fuzzy characteristics of the orientation system. A methodology of designing a fuzzy logic-based adaptive algorithm for stabilization of a transformable flexible multifrequency space object was proposed. The results of simulating the proposed adaptive orientation system were presented.

A Method of Constructing the Mathematical Model of a Discretely Developing Large Space Structure

A new method was proposed to describe the on-orbit mounting of large space constructions that is accompanied by discrete changes in their mechanical structure and dynamic characteristics as controlled plants. Consideration was given to designing the initial (Lagrangian) model for each interval of invariable structure of the discretely developing construction. A graph-based computational procedure of reducing the initial model to the modal-physical one was proposed. Suggested was a method of designing a construction graph model which provides a most compact representation of the changes in the dynamic characteristics of the large space construction that occur in the course of its structural transformation.

Design of modified PD algorithm to control angular motion of large space structure

Consideration was given to the design of an algorithm to control orientation of the large space structure (LSS) in the presence of infralow (less than 0.01Hz) frequencies of elastic oscillations exerting considerable influence on the quality of transients due to closeness of the LSS eigenfrequencies to the frequency of control of the object’s “rigid” motion. Procedure for designing a modified PD-algorithm for orientation of the LSS with infralow frequencies of elastic structural oscillations was described. Methods were proposed for calculation of the coefficients of additional components of the modified algorithm and determination of the LSS eigenfrequency boundary to the right of which the orientation control system is robust to the deviations of the object frequencies or inaccuracy of their definition. Some examples of mathematical modeling of the processes of the relay gyroforce control of LSS orientation using the proposed algorithm were given.

A Fuzzy Logic Adaptation Circuit for Control Systems of Deformable Space Vehicles: Its Design

A fuzzy-logic adaptation algorithm is designed for adjusting the discreteness period a control system for ensuring the stability and quality of control process with regard for the elastic structural vibrations of a deformable space vehicle. Its performance is verified by digital modeling a discrete control system with two objects.

Design of discrete control system of flexible spacecraft maintaining robust stability of elastic oscillations

For the flexible spacecraft with a nonlinear orientation control system using flywheel engines, an approach to making its elastic oscillations robust stable was considered. It relies on a purposeful variation of the boundaries of the stability domains in the parameter space of the spacecraft and controller with the aim of maximizing the number of robust stable elastic modes of the flexible spacecraft. To make its control stable in the large, consideration was given to the possibility of expanding the basic algorithm by adding the sum of the components using the estimated coordinates of the remaining series of low-frequency unstable modes. Presented was an example of mathematical modeling of the proposed spacecraft orientation system which corroborated operability of the approach making the multifrequency spacecraft stable to the elastic oscillations.

Dynamic features of flexible spacecraft control in process of its transformation into a large space structure

AbstractConsideration was given to dynamics of angular motion control of the flexible spacecraft reconstructed into a large space structure. In formal terms, this transformation lies in gradual reduction of the constructive rigidity to small values giving rise to low-frequency (

Some Features of Powered Gyrostabilization of a Large Space Structure Assembled in Orbit

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