Axially Extension-Constrained Toroidal Balloon Mechanism : Application As a Shape-Adaptive Gripper and a Cell Sheet Transfer Device for the Inner Surfaces of Tubular Tissues

In this paper, we propose an axially reinforced toroidal mechanism capable of transferring delicate cell sheets. Several soft grippers based on inflatable membranes have been proposed using elastic rubber materials. However, due to their high compliance, force transmission is insufficient, making it difficult to achieve stable tip eversion for peeling and releasing cell sheets. To address this issue, we develop a toroidal balloon mechanism reinforced in the axial direction using inextensible fibers. The fabrication method is presented, and the stress–strain characteristics of the reinforced membrane are experimentally evaluated. Furthermore, a basic grasping experiment is conducted to demonstrate the effectiveness of the proposed mechanism.