Feline Tongue-Inspired Filiform Microstructure Improving Grasp Performance of Soft Robotic Hands

Soft robot hands perform adaptive grasping stability by flexibly conforming to target geometries without damaging the target. While most improvements focus on macro-scale structural optimization, surface microstructures will also play a crucial role in grasp performance. Inspired by the filiform papillae (FP) on feline tongues, which are barbed structures characterized by high density and moderate deformability that facilitate secure contacting, a feline tongue-inspired filiform microstructure (FTFM) is proposed and integrated into soft robotic fingertips to achieve high grasping ability. By analyzing the morphology and spatial arrangement of FPs, we designed two layout strategies: arc-shaped and cross-shaped arrays. Finite element simulations in Abaqus revealed that the arc arrangement stores 20-25% more elastic strain energy and exhibits more uniform stress distribution, indicating superior elastic adaptability. Grasping experiments under dry contact conditions further validated the effectiveness of FTFM. Compared to conventional smooth-surfaced soft robotic hand (SRH), the developed FTFM-enhanced fingertips improved grasping force by 20-35% as the surface roughness of the object decreased. These results demonstrate that FTFM significantly improves contact friction and adaptive conformity by increasing the number of effective contact points and local deformation. This study provides a novel and scalable strategy for enhancing the performance of soft robotic grippers through bioinspired microstructure design.