An aerial robot capable of changing its shape in full flight

This is a world first: researchers from the Institut des Sciences du mouvement √Čtienne Jules Marey (CNRS/Aix-Marseille University) have drawn inspiration from birds to design an aerial robot capable of changing its shape in full flight. It can change the orientation of its arms, equipped with engines and blades to propel itself like a helicopter, to reduce its wingspan and navigate in full spaces. This work, published in Soft Robotics Journal on May 30, 2018, paves the way for a new generation of massive robots capable of sneaking through narrow passages, an ideal new tool for exploration and rescue missions.

Winged birds and insects have a formidable ability to perform rapid maneuvers to avoid obstacles they encounter during their flight. This great agility is necessary to navigate in very dense places such as forests or very crowded environments. Nowadays, miniature flying machines are also able to adapt their posture (in roll or pitch for example) to pass through a narrow opening. However, there is another type of strategy that is just as effective in allowing birds to cross a narrow passage at high speed despite its imposing wingspan: they can suddenly change their morphology during the flight by folding their wings back and thus pass easily through all kinds of obstacles.

Flying robots will increasingly have to operate in very crowded environments for rescue, exploration or mapping missions. These robots will, therefore, have to avoid the many obstacles and cross passages more or less cramped to fulfill their mission. With this in mind, researchers at the CNRS/Aix-Marseille University Institute of Motion Sciences have designed a flying robot, capable of reducing its wingspan in full flight to pass through an opening without having to fly aggressively, too expensive in energy.

This new robot, called Quad-Morphing, is equipped with two arms on which are fixed two engines each equipped with blades that allow it to propel itself like a helicopter. Thanks to a mechanism mixing flexible and rigid cables, it can modify the orientation of its two arms, that is to say to orient them parallel or perpendicularly to its central axis, and this in full flight. It thus manages to reduce its span by half, to cross a narrow passage, and to redeploy itself, all at a very high speed for an air robot (9 km/h).

The Quad-Morphing’s agility is currently determined by the precision of its autopilot, which triggers a change in arm orientation when approaching a small obstacle based on its position provided by a 3D location system developed in the laboratory. However, the researchers equipped the robot with a mini-camera capable of capturing images at high frame rates (120 frames per second), which will enable it in the future to estimate the size of the obstacle and make the decision whether or not to hold back. Testing of this new version of the Quad-Morphing began in May 2018.