Research on Stiffness Improvement of a Soft Pneumatic Finger Using Skeleton.

Soft pneumatic fingers are compliant structures that improve the adaptability and safety in grasping. Despite high adaptability, low stiffness is the intrinsic problem of the pneumatic grippers that threats grasp reliability. While bending stiffness can be improved by design, soft pneumatic fingers of different types suffer from low torsional stiffness. In this study, a flexible structure is proposed to be integrated into a soft pneumatic finger to enhance the torsional stiffness. Porous layers are adopted on the surface of the skeleton to make bonding with the silicone body. Experiments are designed to compare the twisting angles, rigidity and grasping quality of the skeleton-less finger and the finger with skeleton. The results demonstrated that the grasping performance has significantly improved with the embedded skeleton. Based on the experimental results, strong hands can be designed by creating a balance between the stiffness and flexibility.