Flexure Mechanisms with Variable Stiffness and Damping Using Layer Jamming

Abstract

Flexures provide precise motion control without friction or wear. Variable impedance mechanisms enable adaptable and robust interactions with the environment. This paper combines the advantages of both approaches through layer jamming. Thin sheets of complaint material are encased in an airtight envelope, and when connected to a vacuum, the bending stiffness and damping increase dramatically. Using layer jamming structures as flexure elements leads to mechanical systems that can actively vary stiffness and damping. This results in flexure mechanisms with the versatility to transition between degrees of freedom and degrees of constraint and to tune impact response. This approach is used to create a 2-DOF, jamming-based, tunable impedance robotic wrist that enables passive hybrid force/position control for contact tasks. Keywords: Compliant Joint/Mechanism, Compliance and Impedance Control, Mechanism Design.