Image Credit: EPFL
Drones to help search for victims of natural disasters need the following characteristics: ease of transport, long battery life and robustness. Considering these requirements, a team of researchers from Floreano Lab, EPFL and NCCR Robotics have developed a new drone, which has an insect-inspired folding wing, and will be presenting it at IROS 2016.
Origami techniques were used by researchers to design the wing. This new drone is unique and has a perfect folding structure. Initially, researchers explored folding patterns from nature with high size reduction and one degree of freedom, so that the wing can be folded with single and intuitive movement in a short time span.
Coleopterans (beetles) were found to have both perfect wings and were also able to control deployment from the base of the wing. As a result, researchers found it easier to artificially replicate their wings.
By modeling and prototyping, the original coleopteran blueprints were modified and updated. A significant size reduction was noticed in the artificial crease pattern. In the stowed configuration, the surface is 26% and the wingspan is 43% of the respective dimensions in the established configuration. Despite the complexity of the patterns, the wing can be folded using a single simple movement and has only one degree of freedom.
Locating the crease pattern was one of the main issues that the research team wished to resolve. While using paper for origami the thickness can be neglected, and while designing the wing, it is necessary to use a thicker material so that it can sustain the stresses created during flight.
A 3D folding pattern is created using a thicker material with tiles of different thickness. The inclusion of bistable and compliant folds that are made of pre-stretched latex assures smooth deployment and maximum durability.
The presented wings weigh 26 g, and have dimensions of 115 x 215 x 40 mm when folded, and 200 x 500 x 16 mm when it is deployed. As a result, a surface area of 160 cm
2 and volume of 989 cm 3 is obtained when folded, and when deployed a surface area of 620 cm 2 and volume of 1600 cm 3 is obtained.
The obtained drone has undergone tests against a comparatively rigid wing in a wind-tunnel, and displays only very less good performance when lift or drag values are considered.
The development of a durable, lightweight drone that can be deployed quickly and easily transported enables robots to be used to locate victims after natural disasters. These robots can also be used in space and land explorations, civil inspections and aeronautics.