Mesh Layer Jamming to Cover and Secure Curved Surfaces without Wrinkles

Abstract

Layer jamming technologies, which can alter the stiffness of layered sheets enveloped in an elastic bag via internal vacuum pressure, have typically been used for wearable robots. However, wrinkles on the layer jamming element covering the body impair the feeling of wear and are undesirable. Aligning curved surfaces using sheets without wrinkling requires the sheets to be sufficiently elastic, which reduces the stiffness when used for layer jamming. Mesh sheets (i.e., woven fabrics) cannot elongate along the fibers; however, they can elongate and contract in the diagonal direction by changing their shape. This study proposes using mesh sheets for layer jamming and analytically and experimentally demonstrates their ability to fit curved surfaces without wrinkling. The layer jamming element using mesh sheets changes the bending stiffness in proportion to the internal vacuum pressure and the number of sheets, as in conventional layer jamming. The simple structure and flexibility of the mesh layer jamming are not only suitable for fixing a body or fragile objects but also extend the range of applications using layer jamming technologies. This study also provides a foundation for investigating the wrinkle formation associated with curved surface deformation unique to flexible robots.