Design and Motion Analysis of an Underactuated Finger Based on the Coupled and Self-Adaptive Linkage Mechanism

Underactuated prosthetic hands possess excellent adaptability, yet they often suffer from issues such as complex structure, limited anthropomorphism, and reduced stability. To address these concerns, this paper presents a novel finger with coupled-adaptive functionality, consisting of three joints and two degrees of freedom (DOFs). It exhibits notable anthropomorphism, heightened stability, strong adaptability, and a simplified structure. This finger utilizes a novel coupled-adaptive linkage mechanism, enabling coupled motion in free space and self-adaptive motion while grasping diverse objects. Additionally, a series of simulation analyses have provided evidence that the finger can effectively and stably perform coupled movements and adaptively grasp objects of different shapes and sizes.