Relative Attitude-orbit Coupling Proximity Control for Underactuated Small Spacecraft

In this paper, the relative attitude-orbit coupling control problem of underactuated small spacecraft based on thrust vector control (TVC) is investigated, which can realize rapid proximity orbit maneuver under thrust misalignment disturbance and model uncertainty. First, the relative attitude-orbit coupling dynamics model of the small spacecraft is established, and the underactuated characteristics of the control inputs under the TVC actuator are analyzed. Then, combined with a hierarchical sliding mode structure, a fast terminal sliding mode control method with two inputs and six outputs is designed to solve the underactuated control problem during proximity maneuver. Meanwhile, the adaptive fuzzy observer is introduced to reduce the influence of the disturbance uncertainty on the controller. Through Lyapunov stability proof, the error of a six degree of freedom system can achieve finite-time stability. Finally, the effectiveness of the control method proposed in this paper for rapid proximity maneuver of small spacecraft was verified through simulation.