Design and Analysis of Underactuated Robotic Hands for Spacecraft Surface Attachment

Amid rapid development of space technology, it is necessary to carry out relevant operations in space to ensure long and stable in-orbit operation of spacecraft in complex space environment. The end effector of the space manipulator is the main tool which completes the operational targets, but at present, the end effector can only deal with cooperative targets rather than non-cooperative targets. In order to solve the related problems, this paper investigates the bio-inspired dry adhesion, mechanical attachment devices and underactuated robotic hands at home and abroad, analyzes the attachment principle and application scenarios. Based on the studies, a cable-driven two-finger underactuated robotic hand with mixed attachment mode is designed. In this paper, the flexible joints of manipulators are calculated theoretically and simulated, the static characteristics analyzed, and the integrated manufacturing of joints and knuckles is achieved. The layout of flexible substrate and adhesive pad is reasonably designed to enlarge the contact area between the adhesive pad and the target object. A gripping mechanism with certain flexibility is developed to smoothly grasp objects of different shapes. According to the characteristics of different surfaces, targeted attachment control schemes are designed, a principle prototype built, and the attachment ability of the prototype to various surfaces is verified through tests.