Design of Low Energy Actuation Pathways in Origami-Based Morphing Structures

A hallmark of living systems is the capacity to sense, assess and respond to environmental stimuli. Physical reconfiguration is a pervasive response to the environment for many living systems, such as leg actuation to achieve locomotion or shape change for camouflage or energy harvesting purposes. The soft robotics community has long taken inspiration from this feedback loop and the clear need for tractable morphing strategies to access multiple physical conformations to achieve diverse and energetically efficient tasks. Origami concepts are one strategy to address this morphing structure design problem, by segmenting global shape change into a series of folding operations. The interplay between stretching, folding, and facet bending modes in origami structures generates a complex energy landscape of morphing pathways and multistable states to utilize. However, identifying rigid and deformable folding paths in this high-dimensional and non-convex energy landscape is challenging. To help address this, we leverage the nudged elastic band algorithm to identify low energy folding paths between stable configurations in this landscape. The nudge elastic band technique is a global method that optimizes each point along the path to follow the gradient of the energy function, while also maintaining separation between the points to provide adequate resolution along the path. We demonstrate the utility of this approach for discovering sequenced folding motions, distinguishing between rigid and deformable folding paths, and finding low energy folding paths between stable states in multistabilty origami structures. The presentation will conclude with a discussion how physical reconfiguration can also contribute to the assess domain of the sense, assess, respond feedback loop and the need for strategies to consolidate this feedback loop by maximizing their intrinsic compatibility.