Dynamic Control and Diagnostic Friction Estimation for an SPMSM-Driven Satellite Reaction Wheel

This paper presents a robust dynamic control for a DSP-based satellite reaction wheel driven by a surface-mounted permanent-magnet synchronous motor and its friction estimation from the observed disturbance. In the proposed current control scheme, a proportional-plus-integral feedback controller is augmented with a resonant-based feedback controller and a robust tracking error cancellation controller to yield an excellent sinusoidal winding current command tracking control. The controller design considering compromised performances is conducted. As to the outer loop speed control scheme, the equivalent dynamic model parameters at the nominal case are first estimated, and accordingly, a feedback controller is designed to yield the defined reference response. As the changes of the system parameters and operating conditions occur, a simple robust speed error cancellation control scheme is developed to preserve the defined response trajectory. For a larger speed command change, the ramp command with a suited ramping rate is arranged to avoid long-duration control effort saturation. Meanwhile, an observed disturbance is obtained using a nominal inverse motor drive model, and it is employed to estimate the wheel frictional condition, which can be used in diagnosing the wheel mechanical healthy condition.