Design and Implementation of a Soft-Rigid Hybrid Gripper with Bionic Ligaments and Joint Capsule.

Abstract

Dealing with grasping tasks in unstructured environments, existing soft grippers often exhibit a lack of static stability, while rigid-soft hybrid grippers display limited compliance due to the fixed connections at the joints. To address the challenge of balancing static stability and flexible adaptability, this study designs and implements a bioinspired hybrid gripper combining soft and rigid elements. The gripper draws inspiration from the collateral ligaments and joint capsule structures of human fingers. It employs a tendon-driven mechanism that ensures high static stability while enabling a large range of flexion movements and some degree of deflection, mimicking the dynamic bending of a human finger. Experimental results demonstrate that the hybrid fingers excel in terms of static stability, working range, and output force. Notably, under conditions of extensor tendon pretension, the fingers exhibit finer motion toward the fingertips. The dual-finger gripper performs exceptionally well in various grasping tasks, stably grasping objects of different shapes and weights, such as the Evolved Grasp Analysis Dataset and common daily items. This study offers a novel and straightforward design approach for the development of bioinspired fingers and high-performance robots, holding broad application prospects.