A Metameric Crawling Robot Enabled by Origami and Smart Materials

Metamerism, in biology, occurs when a creature has multiple segments, which are similar in structure and configured in series. True metamerism means that these connected segments include a repetition of all organs and muscle tissues. Earthworms are examples of true metameric creatures. Animals use metameric structures to increase maneuverability and enable multiple modes (gaits) of locomotion along with other functions. This work presents the design of a crawling robot that is inspired by the crawling gait and true metamerism of earthworms. The building block of each segment is a bistable origami structure that extends and contracts its length. The robot moves forward by using directional friction on its feet to enable forward motion and turning. [1]. Using a series of connected origami building blocks provides the robot with a modular metameric structure. This paper presents a true metameric robot design where different segments can be detached and reattached to one another but remain fully functional in each state. The docking system uses shape memory alloy (SMA) wire coils as actuators for a clutching mechanism to disengage the different segments. A directional magnetic arrangement is used to reattach the segments. The actuation architecture exploits the bistability of the origami building blocks to improve the power efficiency of the robot. Future work includes implementing a control algorithm to plan the paths of the different segments and allow for autonomous segmentation and docking in various operational environments.