A novel origami soft gripper based on circular arc creases and leaf-fold structure

Abstract This paper proposes a novel bistable origami soft gripper utilizing arc creases and leaf-fold structure, aimed at enhancing bistable speed and energy conversion efficiency. This study constructed a kinematic model of fold motion using spherical trigonometry theory and the D-H matrix method to investigate the geometric transmission relationship between dihedral and unfolded angles. Subsequently, an energy model combining torsion spring models with the Von Karman plate-shell theory was established to elucidate the potential energy between straight and curved creases. This theoretical framework showed a detailed analysis of the regulatory effects of crease length, curvature, and leaf-fold structure on system energy changes. The initial potential energy of the system and the deformation magnitude required for bistable switching were further enhanced by integrating elastic preload elements into the leaf-fold structure. Some comprehensive tests were conducted to evaluate the effects of various crease types and auxiliary structures on bistable deformation speed, trigger force, and grasping force. Furthermore, grasping experiments were performed on both static multi-attribute object adaptive grasping and dynamic rapid grasping. The results demonstrated that the arc crease significantly enhanced the system energy accumulation efficiency and bistable speed. This design offered notable advantages in structural simplicity and versatile grasping capabilities, providing technical support for diverse soft-grasping applications, including industrial sorting, fruit picking, and similar tasks.