Dynamics and capture strategy study of space rope-based end effectors

Rope-based end effectors have a considerable advantage for capturing large inertial and non-cooperative spacecraft for their large tolerance and characteristics of soft capture. Taking a large space end effector as a research object, capture dynamics equations which includes a flexible rope model and a rope collision model are established according to the Lagrange method and they are verified and corrected by a designed capturing test. Then, a FA-SC-VT (fast-approach slow-contact velocity-tracking) capture strategy is provided for unknown non-cooperative capture problems. Simulation results indicate that compared with traditional uniform capture strategy, the method addressed in this paper can significantly reduce impact force at the end of the manipulator under the same operation time. Besides, the escape problem for low-mass target capture can be effectively solved.