|A drone flying in midair. / Photo by: Freeegooo via Pixabay|
Most aerial drones lack the ability to alter their shape during mid-flight, unlike birds. Thus, researchers at Etienne Jules Marey Institute of Movement Sciences took birds as an inspiration and developed an advanced aerial drone. Their newly created drone can change their shape while flying using quad-morphing.
Aerial drones and robots need to rotate its entire body by 90 degrees in order to fit narrow spaces, like in between the very close walls of two buildings. This aggressive movement can be affected by several factors, such as the size and weight of the robot and the lack of sensors with high refresh rates. Without enough sensors or if it weighs too heavy, the drone might lose its correct position during rotation and then crash into an obstacle.
With the principle of quad-morphing, the researchers replicated how a real flying bird rotates in mid-air. They built an aerial drone with two arms that have two propellers on each arm. This part of the design allows it to fly like a helicopter. To connect the arms to the body, they used a mix of elastic and rigid wires. This design allows the drone to retract the arms, which reduces the wingspan by 48 percent in under 250 milliseconds.
When they tested the aerial drone, the quad-morphing design enabled the robot to fly through a gap of about 50 percent the width of its unfolded wingspan. The design also permitted the drone to finish the flying course for eight consecutive times, with a speed of nine kilometers per hour. The aerial robot has been equipped with a small camera capable of snapping 120 images per second, which let it determine a gap and change its form accordingly.
“Like birds, which are able to negotiate narrow apertures despite their relatively large wingspan, our quad-morphing robot was able to pass through a narrow gap at a high forward speed of 2.5 m.s−1 by swiftly folding up the structure supporting its propellers,” noted the researchers.