Enhancing the Tensile-Shaping Stability of Soft Elongation Actuators for Grasping Applications

Soft elongation actuators are widely applied in soft robotic grippers, providing a promising solution to adjust the grasping range. However, there are some limitations in keeping their tensile shaping stability under high payloads. This work presents a universal variable stiffness mechanism called Cross-Fibre to reduce the deformation and improve the load-bearing capacity of soft elongation actuators. The proposed mechanism is composed of two symmetrical fibre loops in an up-and-down crossed arrangement around the soft elongation actuator. The fibre media on both sides can be stretched compliantly with the actuator, and thus achieve global variable stiffness. In addition, based on the soft elongation actuator with variable stiffness, this work also develops a novel soft gripper prototype for automatically adjusting the grasping range and enhancing grasping applications. Experiments demonstrate that the soft elongation actuator with Cross-Fibre effect has strong tensile-shaping ability, and the soft gripper can stably grasp objects weighting more than 1700 g. Such efficient performance will promote various applications in daily life and industry.