Abstract

Deployable origami-based arrays can offer many benefits for a wide variety of engineering applications because of their ability to stow compactly and deploy to a large area. These types of arrays have been demonstrated for use in solar arrays, heat shields, and more; however, they have yet to be shown in high precision applications such as telescopes. The biggest roadblock to using origami in high precision arrays is align- ment in the deployed state; in optical systems, local (single panel) and global (entire array) misalignment can drastically reduce performance. Precision positioning of origami-based arrays can be a challenge because of the high number of interconnected panels, large motion between stowed and deployed states, and limited space for precision alignment mechanisms/systems. The objective of this work is to answer the question: how might one improve the precision of deployable origami-based arrays? The approach for achieving this objective is to simulate the effects of misalignment on the performance of an array, develop compact precision couplings, build and experimentally test prototypes, and implement designs into origami-based arrays. A practice for defining local and global misalignment in deployable origami-based arrays is suggested, perturbations are applied to the optical model and resulting output recorded, and compensation techniques are applied to restore good performance. Additionally, precision couplings are designed and developed. The coupling is placed in a Z-fold mechanism and two types of degree-four vertex (D4V) mechanisms, all of which are funda- mental components of origami-based arrays. The alignment and repeatability of these mechanisms are measured using a 3D scanner. Deployable lidar telescopes based on the hexagonal twist and flasher patterns are then used as case studies, and the conclusions could be extended to other origami-based systems. The results of optical simulation of the hexagonal twist show that there are several degrees-of-freedom (DoFs) which are more sensitive to misalignment and for which compensation is not effective. The most sensitive DoFs are approximately linear in performance loss and are represented by a slope; they are the local decenter X (0.467% power loss per micron misalignment), local decenter Y (0.463% power loss per micron misalignment), local tilt (0.357% power loss per thousandth degree misalignment), and local tip (0.265% power loss per thousandth degree misalignment) misalignments. The results of the experimental testing conclude that the panels of the Z-fold mechanism have a repeatability of about 0.50°and 0.50 mm. The panels of the D4V mechanisms have a repeatability of about 0.15°and 0.50 mm. These results could help minimize the need for compensation or position sensing and help optical system designers to know which DoFs should be carefully controlled to maximize performance. They also show that precision couplings can be implemented in origami patterns to yield arrays that have better deployed repeatability that traditional designs. This improved repeatability can lead to increased performance of origami-based solar arrays, and new applications, such as optical devices.

Degree

College and Department

Ira A. Fulton College of Engineering; Mechanical Engineering

Rights

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