Park, Junyoung (2008-05). MIMO active vibration control of magnetically suspended flywheels for satellite IPAC service. Doctoral Dissertation. Thesis uri icon


  • Theory and simulation results have demonstrated that four, variable speed flywheels
    could potentially provide the energy storage and attitude control functions of existing
    batteries and control moment gyros (CMGs) on a satellite. Past modeling and control
    algorithms were based on the assumption of rigidity in the flywheel's bearings and the
    satellite structure.
    This dissertation provides simulation results and theory which eliminates this
    assumption utilizing control algorithms for active vibration control (AVC), flywheel
    shaft levitation and integrated power transfer and attitude control (IPAC) that are
    effective even with low stiffness active magnetic bearings (AMB), and flexible satellite
    The flywheel AVC and levitation tasks are provided by a multi input multi output
    (MIMO) control law that enhances stability by reducing the dependence of the forward
    and backward gyroscopic poles with changes in flywheel speed.
    The control law is shown to be effective even for (1) Large polar to transverse inertia ratios which increases the stored energy density while causing the poles to
    become more speed dependent and, (2) Low bandwidth controllers shaped to suppress
    high frequency noise. These two main tasks could be successfully achieved by MIMO
    (Gyroscopic) control algorithm, which is unique approach.
    The vibration control mass (VCM) is designed to reduce the vibrations of flexible
    appendages of the satellite. During IPAC maneuver, the oscillation of flywheel spin
    speeds, torque motions and satellite appendages are significantly reduced compared
    without VCM. Several different properties are demonstrated to obtain optimal VCM.
    Notch, band-pass and low-pass filters are implemented in the AMB system to
    reduce and cancel high frequency, dynamic bearing forces and motor torques due to
    flywheel mass imbalance. The transmitted forces and torques to satellite are
    considerably decreased in the present of both notch and band-pass filter stages.
    Successful IPAC simulation results are presented with a 12 [%] of initial attitude
    error, large polar to transverse inertia ratio (IP / IT), structural flexibility and unbalance
    mass disturbance.
    Two variable speed control moment gyros (VSCMGs) are utilized to demonstrate
    simultaneous attitude control and power transfer instead of using four standard pyramid
    configurations. Launching weights including payload and costs can be significantly

publication date

  • May 2008