Optimal Attitude Control of a Tethered System for Noncoplanar Orbital Transfer Under a Constant Thrust

The problem of an optimal attitude control is studied for a tethered system under a constant thrust in noncoplanar orbital transfer. The contributions of this article mainly include two aspects: first, a noncoplanar orbital transfer scheme and second, a closed-loop optimal control method. Based on a constant thrust, a noncoplanar orbital transfer scheme between two sun-synchronous orbits is proposed, enabling convenient engineering implementation. Compared with existing closed-loop control methods, the hierarchical finite-time attitude tracking control method is presented in the last cycle of the closed-loop optimal control to reduce the error at the final moment. A numerical case of a tethered system in noncoplanar orbital transfer is studied to demonstrate the effectiveness of the proposed control scheme.