Configuration Design of an Under-Actuated Robotic Hand Based on Maximum Grasping Space

Abstract

Capture is a key component for on-orbit service and space debris clean. The current research of capture on-orbit focuses on using special capture devices or full-actuated space arms to capture cooperative targets. However, the structures of current capture devices are complex, and both space debris and abandoned spacecraft are noncooperative targets. To capture non-cooperative targets in space, a lightweight, less driven under-actuated robotic hand is proposed in this paper, which composed by tendon-pulley transmission and double-stage mechanisms, and always driven by only one motor in process of closing finger. Because of the expandability, general grasping model is constructed. The equivalent joint driving forces and general grasping force are analyzed based on the model and the principle of virtual work. Which reveal the relationship among tendon driving force, joint driving forces and grasping force. In order to configure the number of knuckles of finger, a new analysis method which takes the maximum grasping space into account, is proposed. Supposing the maximum grasped object is an envelope circle with diameter of 2.5 m. In the condition, a finger grasping maximum envelope circle with different knuckles is modeled. And the finger lengths with corresponding knuckles are calculated out. The finger length which consists of three knuckles is the shortest among under-actuated fingers consists of not more than five knuckles. Finally, the principle prototype and prototype robotic hand which consists of two dingers are designed and assembled. Experiments indicate that the under-actuated robotic hand can satisfy the grasp requirements. which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Coupled Bending Inwards Motion and Control Strategy Analysis of a Cable-Driven Underactuated Finger

“…The UACT finger that uses tendon-pulley (TP) transmission and parallel four-linkage mechanism (PFLM) to realize the grasp and the grasp capability were illustrated in Ref. [33]. In addition, the self-adaptive grasp process and equilibrium configurations were analyzed in Ref.…”

Design of 3D-Printed Cable Driven Humanoid Hand Based on Bidirectional Elastomeric Passive Transmission

“…Due to the excessive degrees of freedom of the human hand, scientists usually use under-actuated mechanisms when designing artificial prosthetic hands. They ignore some unimportant degrees of freedom and try to preserve the characteristics of human hand as much as possible [17,18]. In 2016, Xiong, et al designed an anthropomorphic hand for replicating human grasping functions.…”

VGS Hand: A Novel Hybrid Grasping Modes Robot Hand with Variable Geometrical Structure

“…Besides, many researchers have proposed some method to optimize the design of the underactuated hand system, Qiao et al designed an underactuated hand based on a maximum grasping space [17], Raymond et al proposed the modular design solution for the underactuated hand [18], and Irfan et al proposed a method for optimizing the fingertip trajectories of the underactuated hand [19]. Their studies help improve the performance in different aspects, but there is still no solution to optimize the pinching grasping mode and achieve the underactuated linear-parallel pinching function.…”