Piecewise attitude tracking control of a gravity gradient microsatellite for coplanar orbital transfer

The gravity gradient microsatellite applied to the exploration of space environment is subject to the problem of orbital transfer between two orbits. The contributions of this paper mainly include two aspects: (1) a segmented optimal trajectory and (2) the piecewise terminal tracking control method. In order to achieve orbital transfer between two coplanar orbits, an optimal controller is designed to obtain a segmented optimal trajectory and then it becomes a problem of attitude tracking in different segments. Compared with traditional finite-time control methods, the adaptive sliding mode control method based on a finite-time tracking error function is proposed, and the stability and robustness of the system can be guaranteed. A numerical case between two coplanar orbits is studied to validate the effectiveness of the control method.