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  • Precession Control Of An Antisymmetric Spinning Spacecraft

    Paper number

    IAC-07-C1.8.07

    Author

    Dr. Katsuhiko Yamada, Nagoya University, Japan

    Coauthor

    Dr. Takeya Shima, Mitsubishi Electric Corporation, Japan

    Coauthor

    Dr. Shoji Yoshikawa, Mitsubishi Electric Corporation, Japan

    Year

    2007

    Abstract
    A certain kind of spacecraft needs to spin its whole body in order to extend flexible antennas by centrifugal forces and to turn its spin axis toward a prescribed direction simultaneously. In particular, a spinning spacecraft with solar paddles sometimes becomes antisymmetric where moments of inertia around axes orthogonal to the spin axis are unequal. In this paper, precession control to change a spin-axis direction of such an antisymmetric spinning spacecraft is considered.   
    
    In case of changing a direction of spin axis, thrusters are generally used to change the direction of the whole momentum of the spacecraft. In this case, nutation motion occurs with changing of the angular momentum, and the thrusters are used again to suppress the induced nutation. In case of an antisymmetric spacecraft, however, a nutation angle (an angle between the whole angular momentum and the spin axis) is not constant, and the remaining nutation sometimes becomes large due to its asymmetry. We propose a new precession control law with thrusters to achieve the changing the direction of the spin axis as well as the suppressing the nutation angle within a specified value. In this control law, the nutation angle and phase are observed and fed back for the thruster injection.
    
    Moreover, the effects of flexible structures on spacecraft are considered. When the spacecraft has flexible structures such as antennas and solar array paddles, these flexible structures interfere with the nutation and change its frequency. The stability of the spin motion is also affected by the flexible structures.  In this paper, the effects of the flexible structures on the control law are analyzed and the results are used to modify the control law.
    
    The proposed control law is examined by numerical simulations. The spin angular velocity and the nutation frequency of the modeled spacecraft are 90 degree/sec and about 0.1 Hz, respectively. The precession control to direct the spin axis in several degrees is applied to this model. The results show that the proposed control law works well for the precession control as well as the nutation suppression.
    
    
    Abstract document

    IAC-07-C1.8.07.pdf

    Manuscript document

    IAC-07-C1.8.07.pdf (🔒 authorized access only).

    To get the manuscript, please contact IAF Secretariat.