The hexagonal twist origami pattern has characteristics that made it a candidate for next-generation deployable space arrays. It has a deployed area that is up to 3.3 times larger than the stowed area, has a single-degree-of-freedom which simplifies actuation, it is flat-foldable making flat positions possible in both stowed and deployed positions, and its rigid foldability means that its motion is enabled by rotation about distinct axes without deformation of its panels. Although the pattern shows promise for deployable systems, it cannot be directly applied with thick materials because of the self-intersection of nesting panels. This paper presents the kinematics and mechanical advantages of the hexagonal twist pattern, addresses the self-intersection problem by implementing five different thickness accommodation techniques and provides metrics for comparing thickness accommodation techniques to determine which would be best suited for a given application. The concepts are demonstrated through two applications: a deployable reflectarray antenna and a LiDAR telescope.

Deployable origami-based arrays can offer many benefits for a wide variety of engineering applications. However, alignment in the deployed state is a primary challenge of these arrays; in optical systems, local (single panel) and global (entire array) misalignment can drastically reduce performance. The objective of this work is to compare the relative sensitivities of different degrees-of-freedom (DOFs) of misalignment in deployable origami-based optical arrays and specify which have the greatest effect on performance. To accomplish this, we suggest a practice for defining local and global misalignment in deployable origami-based arrays, we simulate misalignment perturbations and record the resulting power output, and we use compensation techniques to restore as much lost power as possible. We use a deployable LiDAR telescope based on the hexagonal twist origami pattern as a case study, though the conclusions could be extended to other origami-based systems. From simulation, we find that the DOFs which are the most sensitive to misalignment and for which compensation is not effective are the local decenter X (467% power loss per mm misalignment), local decenter Y (463% power loss per mm misalignment), local tilt (357% power loss per degree misalignment), and local tip (265% power loss per degree misalignment) misalignments. These results could help minimize the need for compensation or position sensing and help optical systems designers to know which DOFs should be carefully controlled to maximize energy output.

In this work, we propose a medical device to be used for correcting pectus excavatum. Pectus excavatum is the most common chest wall deformity, resulting in exercise intolerance, shortness of breath, and chest pain. The current correction method uses a rigid bar that causes moderate to severe pain in patients. The device presented in this paper (termed the Elastic Bar) utilizes the phenomenon seen in pectus carinatum patients in which the patient’s chest wall becomes less stiff after a force is applied for an extended period of time; the device leverages this phenomenon to create gradual correction of the deformity. The elastic bar is a compliant solution to pectus excavatum. We present a set of requirements that determine the success of the compliant solution to correcting pectus excavatum. To analyze the performance of the device against these requirements, two models are developed, one using a fixed-guided modeling approach and the other using an initially curved beam modeling approach. We then use analytical models (developed following the Pseudo-Rigid-Body modeling technique), finite element analysis simulations, and a physical prototype to verify the feasibility of this new device. We find that the three different verification methods agree within approximately 10%. We conclude that this device has the potential to provide improved care to patients with pectus excavatum.