A Soft Finger With Tensile Variable Stiffness Based on the Cross-Sliding Jamming Mechanism

Variable stiffness mechanisms provide an effective means to enhance the load-bearing capacity of soft fingers, but due to the lack of stretchability, their assembly position is often limited to the lower surface of soft bending actuators. Here, a Cross-Sliding jamming mechanism with tensile properties is developed to overcome this restriction. The mechanism is integrated on the upper surface of a soft actuator and can be passively stretched as the actuator bends. By changing the assembly position, the defect of rigidity contact between the conventional variable stiffness fingers and the object is solved, and the disturbance caused by the variable stiffness structure to the contact surface during the jamming process is eliminated. Furthermore, a multi-fingered gripper is assembled based on the variable stiffness soft fingers, demonstrating its effective grasping capability and stability by bending, stiffness, vibration experiments and so on. The reported study provides novel design and application insights for stiffness modulation in soft robots.