A pneumatic soft gripper with pre-deformed stiffener inspired by blowing dragon toys

The movement of toys not only captures attention of children but also informs the design of soft robotics. Pneumatic actuators are a key area of research in soft robotics due to their lightweight and easily controllable characteristic. This study presents the design of a novel pneumatic soft gripper that integrates a soft, minimally stretchable inflatable tube with a pre-deformed stiffener. The motion of the gripper is inspired by the inflation and deflation process of the blowing dragon toys. The gripper’s bending performance and load capacity are analyzed through theoretical force analysis and finite element simulations. Its grasping performance and versatility were evaluated across a range of applications in experiments. Results indicate a consistent trend between theoretical force analysis, finite element simulations, and experimental outcomes. The proposed soft gripper is capable of grasping objects weighing up to 23.32 g and with a diameter of up to 50 mm, achieving a weight-to-grip ratio of approximately 28.38 times its own weight (0.82 g). Compared with conventional lightweight pneumatic soft grippers, the proposed design exhibits superior load capacity. Furthermore, it demonstrates practical applications in tasks such as catching thumbtacks, collecting items, and cleaning pipes due to its excellent bending performance.