Obstacle avoidance in space robotics: Review of major challenges and proposed solutions

Manipulators can be utilized for various purposes during space missions, e.g., Canadarm2 manipulator mounted on the International Space Station assists in station construction and maintenance. Up to now, with only a few exceptions, manipulators in space were always controlled by astronauts or by operators on the ground. However, new ambitious missions, such as on-orbit servicing missions and active debris removal missions, will require a high level of autonomy and will pose new challenges in the field of space robotics. One of such challenges, addressed in this paper, is the problem of obstacle avoidance. This problem has been divided into three topics: (i) collision-free trajectory planning of a space manipulator mounted on a large orbital structure (such as a space station), (ii) collision-free trajectory planning of a manipulator mounted on a relatively small satellite, and (iii) collision-free trajectory planning of a space robot moving in proximity to a large orbital structure. For each topic, major challenges are identified and proposed solutions are reviewed. The presented review shows that the collision-free trajectory planning in space robotics is a very active field of studies, but there are still several open problems that need to be solved before the proposed methods could be applied during on-orbit servicing, active debris removal and on-orbit assembly of large structures.