Research on the stability of magnetic bearing system in magnetically suspended momentum wheel under on orbit condition

Nutation and precession caused by gyroscopic effect are the major factors that influence the stability of magnetic bearing system. Aimed at analyzing the stability problem of magnetically suspended momentum wheel (MSMW) resulted by dynamic couple of satellite and MSMW under on obit condition, dynamics equations of rotor and models of magnetic bearing control system (MBCS) are formulated. Criterions based on the frequency characteristic and root locus of control circuits are applied to verify the stability of nutation and precession under on orbit condition based on the formulated dynamics equations. Due to the rotor's polar moments of inertia is far less than that of around satellite's pitching axis, couple of satellite and MSMW has little influence on nutation stability meanwhile can enhance precession stability. Simulation results prove that the rotational speed at which MSMW loses its stability under on-obit condition is identify to that under on ground condition.