Model-based design of a multistable origami-enabled crawling robot

Origami and kirigami are becoming increasingly more prevalent in robotic systems due to their elegant manufacturability and pseudo-compliant behavior. However, origami-enabled robotic systems are currently designed in an inefficient ad hoc manner due to the complexity of synergistically incorporating compliant origami structures into a system level model. This paper develops a system level dynamic model for the locomotion of an origami-enabled crawling robot. An energy analysis of the primary mechanical components of the robot yields a one-dimensional (1D) equation of motion (EOM) for the robot. The EOM is extended to two dimensions (2D) using a geometric analysis of the origami structures and the constraints imposed by the robotic system. The 2D model is able to represent the robot's forward and directional locomotion. The results of the dynamic model are compared to a kinematics-based model and experimental results. The 2D dynamic model performs similar to the kinematic model of the robot for small forward expansions, but the dynamic model demonstrates superior tracking of the robot locomotion for larger expansions as the system losses increase. The maximum error reported between the dynamic model and experimental results is 10% compared to the 40% error reported for the kinematic model. The paper concludes with a demonstration of how the dynamic model can be used to select the robot design parameters. This paper presents a much-needed framework for the design of origami-enabled robots that can also lead to advances in the control of compliant and pseudo-compliant robots.