A linkage-type underactuated finger for robotic grasping

Underactuated robotic fingers have attracted significant attention in the field of intelligent grasping. However, existing designs often suffer from limited load capacity and poor grasp stability, making them unsuitable for complex application scenarios. Therefore, this study focuses on the design and mechanical performance analysis of a three-joint underactuated finger based on a multi-linkage mechanism. The force and torque distribution across joints are examined through theoretical modeling and static finite element analysis under various loading conditions. Results indicate that the rubber fingertip layer is a high-risk region for strain-induced fatigue. To address this, the Yeoh hyperelastic model is employed to determine a safe strain threshold. Additionally, a biomimetic fingerprint texture is introduced on the fingertip surface to enhance friction and grasp stability. This work provides theoretical and engineering insights for improving the load-bearing capacity and environmental adaptability of underactuated fingers, contributing to the structural optimization and practical deployment of intelligent robotic hands.