Roles of surface patterning in the performance of flexible arms

In contrast to conventional robotic arms, soft arms made of flexible structures are capable of gripping fragile objects through distributed loads and undergoing large deformations in confined spaces, making them promising candidates for industrial applications. Although the effects of material properties and arm geometry on the gripping force are well understood, the influence of surface characteristics, frictional properties, and transitions in contact states on gripping force remains less clarified. We fabricate a pneumatically controlled soft arm with a simple geometric structure through the bubble casting technique proposed in the previous literature and investigate the effect of surface patterning on its gripping force. We systematically vary parameters such as the spacing, height, and width of the surface patterns, finding that are experimentally evaluated, and the results indicate that surface patterns affect the mechanical performance of the arm, thereby enlarging the control space of the arm design.