Capture Dynamics and Control of a Flexible Net for Space Debris Removal

Space debris severely threatens the safety of spacecraft in near-earth orbit. Dragging space debris into the atmosphere to burn is an effective way to remove it. In this paper, the authors focus on capturing irregular and rotating debris via a flexible net. The net capture dynamics, including the constitutive dynamics of the flexible net and the nonlinear contact dynamics with the debris, are established to simulate the movements of the flexible net. The debris dynamics, comprising translational and rotational dynamics, are constructed to simulate its motions throughout the whole process. In addition, an active control scheme is applied to designing the controllers of the flexible net. The presented method can be used to simulate the capture and post-capture process of irregular and rotating debris. Moreover, compared with the previous space debris capture mechanism, the presented flexible net can be opened or closed repeatedly; thus, the proposed flexible net has more potential to capture many pieces of debris in one mission. Numerical simulations show that the flexible net has an excellent capture capability with the presented control scheme. The flexible net can capture the debris rotating with an angular velocity of 6.28 rad/s. Moreover, the debris can be fully enveloped and further dragged away along the expected trajectory. The critical indicator results show that the wrapping of the debris is stable; thus, this method is feasible for future missions