Design, Fabrication, and Testing of a Chain Mail Jamming-Based Stiffness-Changeable Robotic Supporter

This article presents a wearable soft robotic supporter with the function of changeable stiffness for supporting human upper limbs. We employ chain mails as the jamming media to achieve a low-weight design and provide low resistance for free motion and high stiffness for holding arms. Structurally, two stacked chain mails are enveloped by a bellow-like airbag, which has two embedded belts for anchoring. The bellow-like profile increases the flexibility at the normal pressure, making it comfortable to wear. In this article, we present the modeling methods for the simplified analysis of mobility, propose the computer-aided design (CAD) model generator of chain mail to automate the modeling process, and propose the fabrication method of casting airtight silicone airbags with complex profiles enveloping chain mails inside. In the experiments, we quantitatively evaluated the model of mobility and measured the bending modulus, validating the accuracy of the model and the advantages of chain mail jamming. We used a dummy arm to measure the supportable payload and test the performance on holding daily life objects. We also demonstrated the support of human upper limbs, showing the potential in practical application.