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  • Application of the LQG/LTR Method for Attitude Control of a Rigid/Flexible Satellite

    Paper number

    IAC-05-C2.2.03

    Author

    Mr. Luiz Carlos Gadelha De Souza, Instituto Nacional de Pesquisas Espaciais (INPE), Brazil

    Coauthor

    Mr. Rolf Vargas, Instituto Nacional de Pesquisas Espaciais (INPE), Brazil

    Year

    2005

    Abstract
    The main objective of this work is to investigate the influence of the flexibility in the performance of the attitude control system of a Rigid/Flexible satellite. The satellite model is constituted by a central rigid structures to which are connected two flexible appendices.  The flexible appendages are treated as one-dimensional clamped-free bars type beams. The control law with the best performance is projected applying the Linear Quadratic Regulator (LQR) method, the Linear Quadratic Gaussian (LQG) method, and Linear Quadratic Gaussian with Loop Transfer Recovery (LQG/LTR).  The control law based on LQR method shows a good performance when all of the states are considered in the feedback. But this feedback is not possible in the practice, that is, the flexible coordinates and its rates of variation are not measured due to the fact of not having sensors in the flexible parts of the satellite, therefore, it is proposed to estimate these coordinates from measures of the rigid parts (angle and angular velocity) and feedback these states, this technique is known as LQG. However when the filter is introduced, it is observed that the performance of the law of control is degraded. To recovery the good performance obtained with the law based in the LQR and degraded with the introduction of the filter, it is employed the technique known as LQG/LTR.  The results obtained in the simulations have shown that this technique is adequate enough for maintain and recuperate the good properties of performance of the control law projected by the LQR.
    Abstract document

    IAC-05-C2.2.03.pdf

    Manuscript document

    IAC-05-C2.2.03.pdf (🔒 authorized access only).

    To get the manuscript, please contact IAF Secretariat.