A high-order disturbance nutation/wobble control for unbalanced spinning satellites

Abstract

This paper introduces a novel active nutation/wobble rejection control method for spinning satellites enduring thrusting disturbances and reaction wheel limitations. Our approach employs two tilted reaction wheels in reaction-momentum mode, actively controlling wobble/nutation while enhancing disturbance rejection for dynamically unbalanced satellites. This eliminates the need for balancing processes or additional ballast, reducing system weight. A new wheel arrangement and momentum analysis effectively dampens wobble generated by dynamic imbalances. We prove that increasing wheel angular speed about the spinning axis enhances immunity against transverse disturbances. Unlike existing controllers, our method minimizes average thrust/spin axis oscillation while eliminating undesired rates and wobble. Stability is rigorously established through linearized equations and Routh stability criteria. Validation via air-bearing hardware-in-the-loop (HIL) and Monte Carlo tests demonstrates close agreement between predictions and experimental data, highlighting the controller's robustness against high thrusting disturbances. This work represents a significant contribution by achieving active stabilization of unbalanced spin satellites using onboard reaction wheels, potentially paving the way for wider adoption in future spacecraft designs.