Formulation of Stability Conditions for Systems Containing Driven Rotors

Abstract

The much maligned energy-sink analysis is revisited to derive stability conditions for a dual-spin spacecraft that is subjected to possible energy additions by the motor torque. Landon's old idea of subtracting the work done by the motor torque from the energy function is applied to the case when both the platform and the rotor are quasirigid. This is made possible by way of a separation axiom that allows one to obtain an expression for the motor torque. It is shown that this process leads naturally to a symmetric stability condition expressible in terms of Hubert's core energy.