There is an increasing interest in soft robotic grippers as they exhibit an ability to grip objects of differing shapes, sizes, textures, and even deformable materials, all of which present a difficult challenge to traditional rigid grippers. An ideal soft gripper would exhibit universal gripping with high gripping force and consists of low-cost materials with simple fabrication processes. This paper investigates the development of a strong and scalable hydraulic soft tubular gripper (HSTG) using facile fabrication method and low-cost materials. The HSTG which consists of a single long hydraulically actuated artificial muscle, soft 3D printed element, and commercial weaving yarn can expand and contract its orifice to grasp objects using a miniature hydraulic syringe. Grasping experiments show that the new HSTG can successfully grasp convex, nonconvex, and flat objects as well as the ones with cavity. The soft gripper uniquely exhibits high normal contact force at minimal pressure and energy use due to the nature of its working principle. A 26 g HSTG can produce at least 40 N of gripping force, can hold at least 88 N in external gripping mode (~346 times of its weight), 0.34 N in internal mode, and 1.74 N in suction gripping mode. The design and mechanical properties of its components can be fine-tuned to produce tailored performance for different grasping tasks.

Heart rhythm disorders are becoming increasingly prevalent with population aging. Atrial fibrillation ablation (AFA) is a procedure used to treat an irregular heart rhythm (arrhythmia) that starts in the heart's upper chambers. The AFA works by scarring or destroying heart tissue to disrupt aberrant conduction pathways causing the arrhythmia. In hospital cardiac units, a flexible catheter with integrated metal electrode is currently used for the AFA procedure. Despite advances, existing cardiac catheter tips are driven by cable mechanisms which are associated with high nonlinear hysteresis and force loss. In addition, they are also limited to rigid components which require multiple actuators to control the bending tip to reach the complex anatomical corners of the heart. This paper introduces a new soft hydraulic catheter that can achieve bidirectional bending motion via a single soft artificial muscle. The new catheter is also equipped with a portable handle as an ergonomic control interface. To validate the design concept, various prototypes are fabricated and tested including bending angles and generated force capability. Mathematical models for the bending arm are also developed and experimentally validated. The new soft catheter will enable rapid and precise manipulation to reach any target within the cardiac chambers, offering more rapid and focused ablation therapy to improve patient outcomes.