Self-adaptive bistable gripper with Fin Ray effect for versatile grasping

Abstract

Snap-through bistability, a mechanism frequently observed in nature, has been extensively applied in the design of soft grippers due to its rapid response and force amplification characteristics. However, current bistable gripper designs often face challenges in achieving adaptive performance for versatile grasping tasks. This paper proposes a self-adaptive bistable gripper that incorporates the Fin Ray effect and finger–palm synergy within a spring-link bistable structure. In this design, the soft fingers are connected to the bistable structure, with their base motion coupled to the rigid bistable framework through an articulated linkage mechanism. Moreover, the gripper autonomously converts the kinetic energy of a dynamic object into potential energy within the bistable structure, inducing snap-through behavior. Theoretical and experimental analyses were conducted to evaluate the nonlinear mechanical response of the gripper during both static and dynamic grasping scenarios. The results indicate that the bistable gripper exhibits notable self-adaptive capabilities and can grasp static and dynamic objects with response times of tens of milliseconds through active and passive triggering. It also displays versatile capabilities, such as underwater and multi-object grasping. This research contributes to the advancement of bistable gripper design and shows promise for challenging applications such as space debris cleanup, aerial perching, and deep-sea manipulation.