Mechanically Versatile Soft Machines through Laminar Jamming

TLDR

Robotics features two main paradigms: soft machines that are conformable, durable, and safe, and rigid robots that are fast, precise, and capable of high forces. The study aims to bridge soft and rigid robotics by enabling soft machines to emulate rigid robots on command, creating mechanically versatile machines that can switch between soft and rigid behaviors. Laminar jamming, where a laminate of compliant strips becomes strongly coupled through friction under a pressure gradient, is modeled analytically and by finite element methods and then integrated into soft machines to control stiffness, damping, and kinematics. The models enable jamming structures to meet arbitrary performance specifications, and demonstrations show systems that can switch between soft and rigid behaviors, such as continuum manipulators that can rapidly appear and disappear joints.

Abstract

Abstract There are two major structural paradigms in robotics: soft machines, which are conformable, durable, and safe; and traditional rigid robots, which are fast, precise, and capable of applying high forces. Here, the paradigms are bridged by enabling soft machines to behave like traditional rigid robots on command. This task is accomplished via laminar jamming, a structural phenomenon in which a laminate of compliant strips becomes strongly coupled through friction when a pressure gradient is applied, causing dramatic changes in mechanical properties. Rigorous analytical and finite element models of laminar jamming are developed, and jamming structures are experimentally characterized to show that the models are highly accurate. Then jamming structures are integrated into soft machines to enable them to selectively exhibit the stiffness, damping, and kinematics of traditional rigid robots. The models allow jamming structures to efficiently meet arbitrary performance specifications, and the physical demonstrations illustrate how to construct systems that can behave like either soft machines or traditional rigid robots at will, such as continuum manipulators that can rapidly have joints appear and disappear. This study aims to foster a new generation of mechanically versatile machines and structures that cannot simply be classified as “soft” or “rigid.”