Reproducing Orbital Dynamics with Omnidirectional Robots

Abstract

To validate guidance, navigation and control algorithms and to test flight hardware for orbital rendezvous, robotic facilities are an appealing choice. They offer a good reproduction of the orbital dynamics, enabling the testing of rendezvous, docking and in-orbit servicing. To test these procedures, Delft University of Technology has developed its own facility, called the GNC Robotics Lab. This facility consists of two robots with omnidirectional wheels, enabling free-floating movement of flight hardware. These wheels offer an alternative method for the flexibility offered by a robot on a moving rail. On the other side, such wheels represents the main error source due to their peculiar movement. To mitigate this, a closed-loop approach can be exploited. The purpose of this work is to illustrate the effectiveness of such a closed-loop, where the manipulator compensates for the base errors. It is shown that the tracking error can be reduced to less than 1 mm for realistic trajectories.