Soft robotic elbow supporter with self-stiffening chain mail fabrics

This paper presents a novel exosuit designed to augment elbow capabilities using a hybrid actuator that integrates chain mail fabrics with a fiber-reinforced actuator. The actuator provides a bending moment to support elbow movement, while the chain mail enables tunable stiffness through a self-stiffening approach. Unlike conventional jamming-based exosuits, ours does not rely on an external power source to induce the jamming transition, making the exosuit lighter, more efficient, and more comfortable than traditional designs. Rotational stiffness experiments were performed to evaluate the mechanical characteristics and validate the jamming transition within the proposed actuator. Experimental results (at 120 kPa) showed that the hybrid actuator achieved a maximum increase in rotational stiffness of a factor of 13 compared to the fiber-reinforced actuator alone. To define the design space, additional experiments were conducted to evaluate the bending deformation angle, radius of curvature, and output force. Further tests were performed to evaluate the efficacy of the exosuit in enhancing human performance during load-lifting activity. The results demonstrated the ability of the exosuit to support elbow function effectively.