Robust Adaptive Control for Spacecraft Rendezvous with Predefined-Time Prescribed Performance and Input Saturation

This paper proposes a robust adaptive predefined-time control scheme for spacecraft rendezvous maneuvers with the consideration of input saturation and external disturbances. To ensure the rendezvous maneuver completing within a predefined time, a constructive performance function is utilized to impose time-varying constraints on system errors. Subsequently, a nonlinear mapping method is employed to transform the constrained problem into an unconstrained one, thus simplifying the design process significantly. Then, two compensation signals are introduced by the feat of an auxiliary system to optimize the steady-state performance of the system. With the combination of backstepping design and compensating signals, the input saturation constraint will be dealt with properly. All of the closed-loop signals are proved to be bounded under the proposed controller. Finally, simulation results demonstrate the validity of the proposed control scheme.