Image-Feature-Based Integrated Path Planning and Control for Spacecraft Rendezvous Operations

This paper develops an integrated path planning and control framework for a specific problem of image-feature-based spacecraft rendezvous with an uncooperative target. For visibility concerns, the chasing spacecraft is required to approach and synchronize with the tumbling target, as well as to retain the target within the camera's field of view. To this end, an offline path planner is designed by using the gradient of a so-called navigation function to generate a set of desired image trajectories. A novel formulation of the spacecraft relative dynamic model is presented based on current image features and the generated desired ones. To track the desired image trajectories, a robust image-based visual servoing controller is designed via passivity theorem. The stability of the closed-loop system is analyzed using the Lyapunov method. In addition, a hyperbolic tangent function is introduced to cope with the chattering phenomenon caused by the signum function. A scenario of rendezvousing with the defunct Envisat is demonstrated to validate the effectiveness and advantages of the proposed control scheme. Comparative studies with the conventional image-based and pose-based control schemes are performed through numerical simulations, in order to evaluate the target visibility, control accuracy, and fuel consumption under the proposed control scheme.