Robust Adaptive Multi-Target Attitude Tracking Control for Spacecraft Formation Flying Using Terminal Sliding Mode

The paper deals with multi-target attitude tracking control problem for spacecraft formation flying. The leader spacecraft with a rapid mobile antenna and a camera is modeled. While the camera is tracking the ground target, the antenna is tracking the follower spacecraft. The error dynamic is developed, which can convert the tracking-control problem into regulator problem. Based on terminal sliding mode technique, a robust adaptive multi-target attitude tracking control law is developed, where the attitude of the leader spacecraft is represented by the Euler parameter to avoid the singular points. Using Lyapunov stability analysis technique, we prove that the overall closed-loop system is asymptotically stable, and the tracking error will converge to zero in finite time. Since neither linearization nor decoupling was used to simplify the model, the control result is more precise. Validity of the proposed control is indicated via results of the simulations.