PROXIMITY OPERATIONS WITH OBSTACLES AVOIDANCE BASED ON ARTIFICIAL POTENTIAL FIELD AND SLIDING MODE CONTROL

This paper combines Guidance and Control (GC) algorithms for spacecraft proximity operations in presence of multiple obstacles. The proposed guidance algorithm is based on Artificial Potential Field (APF) theory, while the adopted control strategies are first-order Sliding Mode Control (SMC) algorithms. The position control problem is addressed by considering two different first-order methods: the simplex-based and the component-wise SMC. Both control strategies result to be effective and suitable to be implemented by the mono-directional actuation system. These algorithms are suitably designed for a ground test-bed for spacecraft rendezvous and docking experiments, developed within the STEPS project (Systems and Technologies for Space Exploration). The selected algorithms are suitable for autonomous, real-time control of proximity maneuvers with a minimum on-board computational effort. Moreover, the presented strategy is able to avoid obstacles and to manage issues related to the presence of local minima in APF algorithms.