93-136
Spinup Dynamics Of Biaxial Gyrostats
Christopher D. Hall*
Abstract
We study the spinup dynamics of gyrostats containing two axisymmetric rotors which are parallel l to principal axes of the gyrostat. Spinup of the rotors is due to small constant torques applied by the platform. The dynamics are described by five first-order ordinary differential equations. Conservation of angular momentum is used to reduce the order by one; this reduction separates the fast and slow variables so that averaging may be applied giving a further approximate reduction to a system of three equations for the slow variables. Visualization of spinup dynamics in the slow space mekes it possible to predict and avoid resonance conditions which may result in abrupt orientation changes.
*Assistant Professor Department of Aeronautics and Astronautics Air Force Institute of Technology, Wright-Patterson Air Force base. Ohio 45433. Member AAS AIAA.