Trade Space Exploration of a Magnetically Actuated Miura-Ori Structure

Origami folding patterns are finding use in novel applications where actual device response depends on current, possibly intermediate, shapes on the path toward the final target shape. This works investigates one origami pattern, developing metrics for performance that incorporate traditional shape approximation and actuator efficiency, while adding proxy measures of adherence to the target folding path. Magnetically actuated Miura-Ori structures were develop using an initially heuristic strategy involving experiment, observation, and computation before being studied using trade space optimization/visualization. Constructed from PDMS substrates, notched to promote the crease pattern, and neodymium magnets, four initial configurations were chosen based on heuristic arguments that (1) maximized the amount of magnetic torque applied to the creases and (2) reduced the number of magnets needed to affect all creases in the pattern. Experiments were conducted, and calculations performed, on prototypes from each configuration to determine their degree of closure for a fixed maximum field strength, their ability to follow the ideal Miura-Ori folding pattern, and the amount of work theoretically performed by each magnet on each crease. Each configuration was further optimized theoretically using the Army Trade Space Visualization (ATSV) software. A final prototype was constructed following the weighted sum scoring of the four now optimized configurations. Somewhat surprisingly, trade space optimization showed that the configuration with the highest number of actuators was theoretically the least effective per magnet at delivering torque to each crease. Unsurprisingly, optimization was successful at increasing the amount of work theoretically apportioned to each crease. Overall, though the winning configuration experimentally outperformed its initial, non-optimal counterparts, results showed that the choice of optimum configuration was heavily dependent on the weighting factors within the objective function. These results highlight the ability of the Miura-Ori to be actuated with external magnetic stimuli, the effectiveness of a hybrid heuristic - trade space design approach that focuses on the actuation mechanism, and the need to address path-dependent metrics in assessing performance in origami folding structures.