Session: 12-20-01: Functional Origami and Kirigami-inspired Structures and Metamaterials

Paper Number: 109491

109491 - Collapsible Origami-Based, Drop-Deployable Micro Air Gliders 

This paper reports on the design, fabrication, and testing of a collapsible micro-air-vehicle (MAV) with bio-inspired, origami-based fixed wings. Foldable wings can commonly be found in nature, e.g., birds, bats, and flying insects. Some wings, for example those of ladybugs, are not controlled by muscles but by joints that have bi-stable open-closed positions. The wings have a particular folding pattern that allows them to collapse and expand via the flexible joints when subject to a trigger force. Using this as inspiration, five different foldable wing configurations (called Triangle, Paper Airplane, Tapered Wing, Swept-forward, and Swept-back) were created and evaluated for use for a collapsible MAV that can be stored and deployed in compact form minimizing its wingspan. Upon release, the wings can be triggered and self-reconfigure enabling the MAV to fly.

The common design feature of the wings is that the folding patterns involve non-zero-thickness panels  which can be stacked between standoffs connected by the joints. All the layers are oriented parallel to each other resulting in compactness and ease of storage. It was determined that flat foldability requires:

1) the sum of opposite angles of a panel must be 180° and 2) if there are n number of valley folds, there must be n ± 2 mountain folds in a panel. This ensures that there are an even number of folds at each node. Determination of suitable patterns were found primarily by trial and error.

To enable the wings to open and hold their configuration three self-locking, bi-stable joints (elastic-hinge, friction-based, peg locking) were designed and evaluated. Each joint can be fabricated by an entry-level, consumer 3D printer with dual extrusion of a more-rigid (e.g., ABS) and a flexible material both of which are inexpensive and readily available. The geometry of the joints is such that there is a stable closed or folded state and a stable open state that can be locked into place.

Flight tests were conducted to evaluate the performance of combinations of the wing and joint designs. For this study, the primary requirement was for the final prototype to be dropped in its folded configuration and then be able to open and fly to the ground like a glider (e.g., what would be expected of a paper airplane). Through testing iterations, appropriate tail structure and flight control surfaces (e.g., elevators) wings were identified. In addition, discrete masses were added to wings to alter their mass distribution as needed. With these modifications, four of the prototypes were able glide through the air when thrown or dropped nose down in a folded configuration from a height of approximately 10 m (third story window). Both qualitative and quantitative results are presented that evaluate gliding performance. Qualitative evaluations describe how well the MAVs level out from a vertical to horizontal position and visually observing the straightness of its flight path. Quantitatively, the time the MAVs took to level out and then to land on the ground was recorded. The flight tests demonstrate that the prototypes can be deployed in a collapsed configuration and then open successfully glide to the ground.

Presenting Author: Christopher Lee Olin College of Engineering

Presenting Author Biography: Chris Lee is a Professor of Mechanical Engineering at Olin College of Engineering

Authors:

Hannah Kolano Olin College of Engineering
Miranda Lao Olin College of Engineering
Anil Patel Olin College of Engineering
Maxmilian Wei Olin College of Engineering
Jingyi Xu Olin College of Engineering
Christopher Lee Olin College of Engineering