Fixed-Time Disturbance Observer-Based Prescribed Performance Control of Rigid Spacecraft

This is the authors' abstract. We don't add key points for this paper.

This paper deliberates on the construction of a fixed-time disturbance observer (FTDO)-based dynamic surface control (DSC) for attitude tracking of rigid spacecraft affected by asymmetric full-state prescribed performance (AFSPP) constraints. Distinct from conventional disturbance observers that rely on disturbance upper bounds or system initial conditions, an FTDO with dynamic observer gains is offered to approximate the lumped perturbations originating from external disturbances and inertia uncertainties. Subsequently, fixed-time performance functions are exploited to guarantee that attitude tracking errors converge to the specified scopes within a limited time. Furthermore, an FTDObased DSC protocol incorporating a nonlinear filter is put forward to alleviate the computational complexity in backstepping control while enhancing control efficiency. Also, the practical fixed-time stability of all closed-loop signals and the compliance of the AFSPP restrictions are rigorously verified via the Lyapunov theory. Finally, case studies are included to reveal the practicability of the presented methodology.