| Space robotics is considered one of the most promising approaches for on-orbit-servicing (00S) missions such as docking, berthing, refueling, repairing, upgrading, transporting, rescuing, and orbital debris removal. Many enabling techniques have been developed recently and several technology demonstration missions have been completed. A number of manned servicing missions were also successfully accomplished but unmanned real servicing missions have not been done yet. All of the accomplished unmanned technology demonstration missions were designed to service perfectly known and cooperative targets only. Servicing a non-cooperative satellite in orbit by a robotic system remains unproven and further research is needed.;In this work we present the development of two independent control strategies for a space manipulator to capture a tumbling object with 00S purposes. In the first strategy, the idea is, first predict a target time, location and speed of the tumbling object for the robot to intercept with, such that, when the robot hand physically touches the object, it will transfer a minimal angular impulse to the base satellite. Then, an optimal motion trajectory and the corresponding joint torques will be generated to control the robot to reach the object at the targeted time and location.;The second strategy is bio-inspired in tau theory, which according to ecological psychology, represents the way that an animal or a human approach an object to capture it. In this case, firstly, the predicted optimal time and point to capture are obtained similarly as in the above mentioned methodology. After that, a tau-based final approaching path planning method is used to find the motion trajectory which will guide the robot to reach the target at the predicted contact location and time.;Both of the strategies are validated in a simulation environment and the results obtained indicate that each one of the strategies offers some advantages that can be beneficially applied to the space roboticsfield to OOS. |
