Exploring Modal Switch in Metamaterial-Based Robots

Mechanical metamaterials are microscale pat- terned structures that are designed to have specific mechanical properties at a macro-scale that are atypical of natural ma- terials. Robotic manipulators composed of these materials can exhibit deformation and motion capabilities that can be cus- tomized and easily fabricated. However, as of now, the motion capability of such manipulators are encoded in their physical composition and cannot be changed. This paper presents multi- modal metamaterial-based robot prototypes which can switch between the behaviors found in two different metamaterials. Two such robots are explored, a bending/shearing robot and a bending/twisting robot. The robot design is described in detail, including how the robots toggle between behavior modes via mechanical actuation of a sliding rod insert. Multi-modal robots are compared to their single-mode equivalents to character- ize their capabilities. The single-mode behaviors are largely preserved in the multi-modal innovations. The multi-modal prototypes also demonstrate variable rigidity. We discuss the feasibility of using robots of this design as part of a robotic surgical system.