Origami-based structures for multi-modal Robots – OrigaBot

he OrigaBot project began with a kick-off meeting in Marseille in February 2019 in order to carry out a common reflection between all the partners on the 3D geometric origami structures likely to be interesting for the project and also to envisage their actuation. In the large catalogue of geometric origami, we have favoured the so-called tubular 3D origami so as to eventually implement a robot capable of rolling or flying by changing its shape. No less than 7 project meetings have been held since the beginning of the project. We have also set up meetings every 15 days or so between the PhD students involved in the project.

We have characterised the maximum thrust available for a rotor (about 350 grams) and a bench to evaluate the dynamic stability of the prototype being finalised (figure 2). The test bench will be replicated in Strasbourg (ICube) and Marseille (ISM) in order to develop the stabilisation control laws and to test the actuation of the origami structure and its influence on the rotor aerodynamics. The modelling of the kinematics of the Kresling tower by ICube led to a publication. We have worked on a new type of multistable Origami structure (Bendy Straw) reproducing for the first time in origami the kinematics of the flexible tubular straw linkage (accordion, see figure 3). This structure, whose mechanical properties are very promising, will be considered for the design of the future OrigaBot robot with multimodal locomotion. This work is the subject of a publication submitted to the Journal of Mechanical Design. For the on-board actuation of the OrigaBot robot, we are focusing on the integration of shape memory alloy (SMA) actuators in antagonistic assembly. The work of a doctoral student at FEMTO-ST is focused initially on the handling of the various models available in the literature and the evaluation of the performance of these models on the prediction of the performances. A review article entitled «A Review of SMA-based Actuators For Bidirectional Torsional Motion: Application To Origami Robots« was submitted to the journal Frontiers in Robotics and AI in a special issue «Origami Robots: Design, Materials and Applications«.
To ensure optimal energy density and compactness for the intended application, we chose AMF torsional actuators in antagonistic mounting. The use of the Lagoudas model and its validation by a finite element model allow us to design torsional actuators with complex shapes.

A test bench will be replicated in Strasbourg (ICube) and Marseille (ISM) in order to develop the stabilisation control laws and to test the actuation of the origami structure and its influence on the rotor aerodynamics. The stabilisation of the first OrigaBot in mono-spinner configuration should be implemented by summer 2021 with a publication submitted in September 2021. A second complete prototype capable of rolling and flying and with an actuated Origami structure will be planned for late 2022 - early 2023 with a publication in a very high ranking journal expected in late 2023.

- E. Bernardes and S. Viollet (2021) Design of an origami bendy straw for robotic multistable structures, J. of Mechanical Design, submitted.
- Kejun Hu, Kanty Rabenorosoa and Morvan Ouisse, A Review of SMA-based Actuators For Bidirectional Torsional Motion: Application To Origami Robots, Frontiers in Robotics and AI, submitted.
- J. Berre, F. Geiskopf, L. Rubbert, P. Renaud
Origami-Inspired Design of a Deployable Wheel, MTM & Robotics 2020, Timisoara, Romania, Springer, Mechanisms and Machine Science, Volume 88, octobre 2020, doi:https://doi.org/10.1007/978-3-030-60076-1_11
- S. Viollet (2021), Multimodal locomotion in robotics : an origami approach, International Workshop on Embodied Intelligence, march 2021.