Predictive Nutation and Spin Inversion Control of Spin-Stabilized Spacecraft

Abstract

Thus far, nutation control and spin inversion maneuvers have been treated from different perspectives for the stabilization of spinning spacecraft. This paper tackles these problems in a unified framework by applying a predictive control for minor-axis spinners with a transverse wheel. Predictive control seeks a control input minimizing a cost function in the form of the weighted sum of predicted output and control effort. The two-step design approach of the proposed application defines the cost as 1) angular momentum only on the orthogonal plane to the minor axis and 2) angular momentum augmenting the error of the desired minor axis. Corresponding weight parameters are designed based upon physical meanings, and a final desired state or online time-varying trajectory is suggested as a reference for successful and effective control. Both control laws are shown to be essentially globally stable about the minor-axis spin, including flat-spin recovery. However, while the final polarity of the first is unpredictable, the second is capable of spin direction control enabling inversion maneuvers. Simulation results also verify robustness of the proposed controllers against assumable system uncertainties.