Saturated explicit reference governor for spacecraft constrained attitude reorientation control

In this work, a saturated explicit reference governor (ERG) control scheme is proposed to achieve attitude reorientation maneuver in the presence of pointing constraints and input saturation. Specifically, a saturated controller is first proposed to ensure the asymptotic stability of the closed-loop system. Then, an add-on ERG scheme is designed for guaranteeing constraints satisfactory. A safe trajectory is designed based on the potential functions, and both keep-in and keep-out constraints are enforced by keeping attitudes within the safe invariant sets. Additionally, a hysteresis mechanism is introduced in the manipulation of reference to avoid the unwinding phenomenon. Numerical simulations are included to demonstrate the efficacy and performance of the proposed control strategy.