Development of a cable-driven soft actuator with variable stiffness using mechanical fiber jamming structure

Soft robots have a compliant and flexible nature that allows them to work safely in contact with the environment and humans. However, soft material has low stiffness, which limits its applications to those that require more stiffness. Fiber jamming is a method to increase the stiffness of a soft actuator, allowing for the tuning of stiffness in multiple bending planes to increase its applications further. In this research, we introduce mechanical fiber jamming to increase the stiffness of cable-driven soft actuators as an alternative method for jamming from a pressure source in a typical design. The proposed design activates jamming from the actuator body and cables, which are also used to drive the actuator. The experiments demonstrate the effectiveness of our design in varying stiffness. In addition, we create a prototype with two sections of the actuator to increase the mobility of the actuator and demonstrate the effectiveness of variable stiffness.