PROJECT TITLE :

6-DOF integrated adaptive backstepping control for spacecraft proximity operations

ABSTRACT:

Relative motion management with half dozen degrees of freedom (vi DOF) is investigated for a chaser spacecraft with parametric uncertainties to approach an unknown tumbling area target. Not like the standard relative motion model described within the target orbital frame, the relative motion model formulated in the chaser's body-fastened frame will simplify modeling and management style for spacecraft proximity operations, whereas the chaser's thrust misalignment and therefore the natural couplings between relative translation and relative rotation are considered in the half dozen-DOF integrated dynamics. After the coupled relative motion dynamics are modeled, a six-DOF integrated state feedback controller is designed by combining the classical backstepping technique with a simple norm-estimation adaptive method to realize good control performance and reduce the computational burden. The chaser's and target's unknown inertial parameters, unknown thrust misalignment, and upper certain of unknown disturbances are estimated by on-line adaptive laws. Ultimately, uniformly bounded convergence of the relative position and relative attitude is proved via Lyapunov analysis. The performance of the proposed controller is demonstrated through numerical simulations.