Stiffness Design of Active Capture Claw-Type Docking Mechanism for Lunar Sample Return

Abstract

The docking mechanism is the key system for realizing the lunar-orbit docking mission of two spacecraft, which needs to have both capture correction and connection hold functions. The different stiffness requirements between the capture correction process, where low stiffness is desired, and the connection hold process, where high stiffness is desired, pose a significant challenge to the design of the docking mechanism. In this paper, an active capture claw docking mechanism is designed. Under the constraints of being lightweight and having an envelope size, three sets of independent claw mechanisms are designed using the modular design idea to achieve the performance optimization and function integration of the docking mechanisms. The theoretical model of the collision dynamics between the active and passive docking mechanisms is established; the stiffness value range of the docking mechanism is determined, and the typical docking conditions are simulated and verified. The results show that the stiffness design in this paper can satisfy the requirements of the two docking processes. The active capture claw docking mechanism developed was applied to the lunar surface sample return mission successfully and played an important role in the lunar-orbit docking mission.