Development of a novel end-effector for an on-orbit robotic refueling mission

At present, the space station on-orbit service is still rapidly developing, and on-orbit refueling operation has not been fully realized. During the process of an on-orbit robotic refueling mission, the pipe disconnectors are artificially docked, and the problems of low efficiency and a long operation period are common. From the perspective of bionics, this paper studies the kinematics of the upper limbs in the manual docking process of the pipeline quick disconnector and analyses the redundant degrees of freedom in the manual docking process. In this paper, without changing the original structure of the quick disconnector, a five-degrees-of-freedom multifunctional end-effector imitating the human hand with a compact structure and a light weight was created, which can realize the automatic docking of the quick disconnector in the pipeline. The quick disconnector docking in the refueling system is simplified from the original manual, two-handed operation to a single-end-effector operation with a single mechanical arm. Compared with a dual-arm robot, a single-arm robot has the advantages of internal force sealing, a stable structure, a higher docking accuracy and a lower cost. The common rigid body contact collision dynamics problem is thus studied. The contact dynamics model between the 'quick disconnector and the robot end-effector' is established by the equivalent spring damping model method. The experimental prototype was developed according to the structure of the end-effector to complete the construction of the refueling robot experimental platform. A simulation and experiment were conducted to verify the advantages and effectiveness of the structure.