Design of an Origami Bendy Straw for Robotic Multistable Structures

Abstract

This paper presents a soft cylindrical multi-stable origami structure based on “bendy straws”, consisting of multiple conical frusta mimicking the structure of a flexible drinking straw. These frusta are connected in such a way that the whole structure is axially multi-stable, having a stable compressed state in which its smallest frustum is collapsed. The bendy straw structure can also be modified so that the smallest frustum collapses only partially, keeping the structure in a bent state. We studied the geometry of a similar structure consisting of polygonal frusta instead of conical ones, and used this geometry to design a non-rigidly foldable origami pattern folding into a similar origami bendy straw structure. Most of the origami structures presented so far have been modeled from rigidly foldable origami patterns: these origami structures do not rely on deformation, and cannot use it to their advantage; whereas the non-rigid origami structure presented here features multi-stability. We have established that this origami structure is not only axially multi-stable, but that it can also be kept in a bent state, thanks to the use of pop-through defects (PTDs). The origami bendy straws studied here were made from paper (with a density of 90g/m2) bi-laminated with a 42.5-micron thick plastic film. A digital dynamometer was used to study the forces required to compress and expand a single origami bendy straw, create and reverse a PTD, and bend an origami bendy straw using PTDs.

Dynamics of reconfigurable straw-like elements

“…A recent study started shedding light on the static behavior of straw-like elements by showing empirically and theoretically that their multistability originates in internal stresses [15]. A similar local multistability was demonstrated in an origami implementation of 'bendy straws', where pop-through defects gave rise to a single non-axial stable state of each unit-cell [16]. In another recent article, the authors produced a two dimensional array of uncoupled straws restricted to deform uniaxially [17].…”

Robotique et origamis

“…La figure 2 montre la polyvalence et la diversité des structures de pliage qui peuvent conduire au développement de structures innovantes en les associant à des micro-actionneurs. Les mécanismes économes en énergie basés sur les origamis peuvent inclure des propriétés mécaniques de bistabilité ( [10,11]) résultant des effets de flambage ou de la cinématique bio-inspirée basée sur des mécanismes de plante carnivore ( [12,13]) : l'énergie n'est requise que très transitoirement dans ces dispositifs pour plier les structures auxquelles sont fixés les micro-actionneurs. Des techniques inspirées de l'origami ont récemment été utilisées pour créer des structures tridimensionnelles en pliant des matériaux bidimensionnels ( [3,14,15]).…”

“…Les robots parallèles à base d'origami sont beaucoup plus développés car ils bénéficient de l'actionnement localisé à la base [32,33,34,35,36]. Une étude récente a proposé la conception et la réalisation de la paille souple multistable en origami [11]. Cette structure permet de reproduire un structure cylindrique flexible ayant des propriétés de variation de longueur et de changement de rayon de courbure tout en maintenant une courbure donnée même en l'absence d'efforts externes (multistabilité).…”

Development of a 3D Printed Origami Robotic Arm Inspired by Elephant Trunk

“…Compared to other origami robotic arms, our design and fabrication approach has advantages of better durability, better resilience, and easy fabrication, and the structure is highly modular. Our proposed structure design adapts "bendy straws" designed by Evandro Bernardes who introduced mathematical models of origami designs and prototypes of paper origamis [6]. The proposed design is adequate for various manipulations with retracting in great distance and tilting in all directions.…”