Embedded and controllable shape morphing with twisted-and-coiled actuators

摘要

Shape morphing, meaning a structure can first morph and then lock into another shape, can be applied to robot designs to endow robots with adaptive morphology for increased functionality and adaptivity. In this paper, we introduce a novel shape morphing scheme enabled by a new artificial muscle: twisted and coiled actuators (TCAs). This new actuator is purely soft, low cost, and electrically driven. Embedding a TCA and a thermoplastic material with variable stiffness into soft materials, we create a miniature shape-morphing link. We also establish a general model to predict the steady-state shape of the link given an input power applied to the TCA. Experiments are conducted to characterize parameters and verify the proposed model. Finally, we demonstrate this shape-morphing link can serve as a link in a mechanism to change the trajectory of its foot or endpoint. We envision that such a new shape-morphing scheme can enable robots to leverage the same mechanical design for different functions.