The finite-time robust control for spacecraft rendezvous and docking

In this paper, the problem of relative position control for rigid spacecraft in rendezvous and docking is investigated. We propose a control scheme with finite-time convergence based on the linearized dynamic model obtained from the Hill-Clohessy-Wiltshire (HCW) equations, in the presence of external disturbance. By constructing a particular Lyapunov function, we confirm the convergence of the proposed controller theoretically. Furthermore, to alleviate the chattering phenomenon while at the same time guaranteeing the finite-time convergence, we introduce a new function into the controller. Finally, simulation results are presented to elucidate the effectiveness of the control strategy.