Laminar Jamming Flexure Joints for the Development of Variable Stiffness Robot Grippers and Hands

Abstract

Although soft robots are a good alternative to rigid, traditional robots due to their intrinsic compliance and environmental adaptability, there are several drawbacks that limit their impact, such as low force exertion capability and low resistance to deformation. For this reason, soft structures of variable stiffness have become a popular solution in the field to combine the benefits of both soft and rigid designs. In this paper, we develop laminar jamming flexure joints that facilitate the development of adaptive robot grippers with variable stiffness. Initially, we propose a mathematical model of the laminar jamming structures. Then, the model is experimentally validated through bending tests using different materials, pressures, and number of layers. Finally, the soft, laminar jamming structured are employed to develop variable stiffness flexure joints for two different adaptive robot grippers. Bending profile analysis and grasping tests have demonstrated the benefits of the proposed jamming structures and the capabilities of the designed grippers.