Automated Rendezvous & Docking (AR&D) without Impact Using a Reliable 3D Vision System

Abstract

There are several space missions that will require capabilities for Automated Rendezvous & Docking (AR&D) without human intervention. Advances in sensor technology and on-orbit flight control are critical to the success of such missions. This paper describes AR&D of a free-floating object with uncertain dynamics by integrating a vision system, a dynamic estimator, and an optimal controller. A Kalman filter (KF) estimator and an Iterative Closest Point (ICP) algorithm in a closed-loop configuration are used for estimating not only the states of the target object but also its dynamics parameters. Subsequently, the estimated states and parameters are used by an optimal controller to derive a chaser spacecraft to intercept the target object with zero relative velocity at a rendezvous point. This arrangement allows smooth and impactless docking to a free-floating object with uncertain dynamics. Furthermore, continuous pose estimation for the purpose of the feedback is possible even with temporally failure of the vision sensor as a consequence of the prediction estimate capability of the dynamic estimator. Experiment results obtained from robotic docking to a tumbling satellite using a laser camera system are appended.