Adaptive Robust Control with L2-Gain Performance for Autonomous Spacecraft Proximity Maneuvers

This paper investigates relative motion control for a rigid spacecraft with parametric uncertainties and external disturbances to approach an unknown tumbling space target. State feedback controllers for relative translation and relative rotation are designed based on a unified adaptive robust control with L2-gain performance. Parametric uncertainties and unknown dynamic couplings are compensated online with adaptive update laws. An external disturbance is treated as a bounded perturbation input for the system. To synthesize the controllers and achieve a prescribed L2-gain performance index, the feedback gains of the controllers are designed by solving linear matrix inequalities. Indeed, perturbation attenuation with respect to the controlled output is ensured in the L2-gain sense. Moreover, in the absence of perturbation input in the closed-loop system, asymptotical convergence of the relative position and relative attitude are proved by using the Lyapunov stability theory. Numerical simulations are perf...