LBLSTM observer based performance guaranteed tracking control for flying around a non-cooperative target

This paper investigates fly-around control problem for a non-cooperative space target subject to uncertain space perturbations, actuator saturation and unknown maneuvers of the target. Firstly, to provide the full state information required by prescribed performance control (PPC) method, a Lyapunov based long short-term memory (LBLSTM) observer is designed to adaptively estimate the relative motion velocity in line of sight (LOS) coordinate system. Then, based on the estimated information from LBLSTM observer, a performance guaranteed controller is developed via utilizing PPC technique. Compared with existing fly-around control methods, the key advantage of the proposed approach lies in its ability to accurately estimate the relative motion velocity without relying on prior knowledge of uncertain dynamics. This capability enables high-quality tracking control even in the presence of measurement errors and unknown maneuvers. Finally, two groups of circular and elliptical fly-around illustrative examples are organized to validate the effectiveness of the proposed control method.