Sheath-run artificial muscles and methods of use thereof

Abstract

Sheath-run artificial muscles (or SRAMs) are described in which the dimensional changes and/or modulus changes of a sheath on the surface of a twisted or coiled host yarn or fiber drives torsional and tensile actuation. The sheath-core artificial muscle includes a sheath on a coiled core yarn or fiber that has inserted twist, in which the sheath does not include a yarn, the coiled core yarn or fiber includes a core yarn or fiber, the sheath can change volume, modulus, or a combination thereof when actuated by an influence source to drive actuation, and the influence source is selected from a group consisting of absorption processes, desorption processes, changes in temperature, changes in external pressure, changes in a magnetic field, changes in an electric field, exposures to actinic radiation, electrochemical charge and discharge, chemical reactions, and combinations thereof. These sheath-run muscles can be used for diverse applications, such as robots, robotic devices, energy harvesters, muscles that enable electrical energy harvesting, comfort-adjusting textiles, comfort-adjusting clothing, bio-powered intelligent muscles that control the release of drugs, muscles for appropriate drug delivery, intelligent muscles that sense their environment and actuate in response, muscles for artificial limbs and orthotic gloves, muscles for haptic applications, muscles that can perform in extreme environments, and muscles for intelligent solar panel positioning.