Dynamic Closing Point Determination for Space Debris Capturing via Tethered Space Net Robot

Tethered space net robot (TSNR) is treated as one of the most promising space debris capturing methods. To perform a successful net capture mission, it is necessary to determine the net closing point for four maneuvering units to make the net fully close around the debris. In the previous studies, a fixed point (FP) is provided as the position for maneuvering units to converge. However, the FP cannot be easily given, especially for the situation that the debris does not contact in the center of the net and the debris in the state of tumbling. In this article, we propose a method to determine the 'dynamic closing point' (DCP), which is a dynamic position moving with the motion of the four maneuvering units and suitable for maneuvering units to converge. First, the dynamic model of TSNR is derived. Then, the 'DCP' is defined based on the position of the four maneuvering units. Taking a cylindrical target as the example, the DCP and FP are chosen as the different net closing methods to show the net closing performance of TSNR. The simulation results verify that the proposed DCP is more efficient and fuel-saving.