Dude, is that a drone in your pocket?
Disaster relief efforts are among the top use cases that drone advocates have been petitioning in recent years, and rightfully so. Their unmatched ability to be released over a dangerous or inaccessible area to snap photographs and make contact with survivors far exceeds other methods being implemented today. With this in mind, researchers at EPFL and NCCR Robotics have developed an origami-inspired UAV that not only folds down into a pocketable square, but actually opens itself up and takes flight in a fraction of a second.
“You can take it out of the box, switch on the motor, and it’s ready to fly,” explained Dr. Stefano Mintchev, a professor of bio-inspired robotics at EPFL in Switzerland.
The current prototype, which was recently unveiled at the International Conference on Robotics and Automation in Seattle, features a set of arms comprised of fiberglass and inelastic polyester with propellers at their ends. When activated, the force of the rotors pulls each foldable arm out into its extended position where it’s held in place by magnets. In order for this to work, the rotors must turn in the same direction, causing the arms to rotate out the opposite way and open around two vertical folds. When the arms are fully extended, their upper section moves horizontally and locks the segment open. Otherwise, when not in use, the arms fold up in the shape of a trapezoid for easy stowing.
To maintain stability, two of the quadcopters rotors must turn clockwise, with the other two turning counter-clockwise. A sensor detects when the rotors are fully extended, then reverses the spinning direction within 50 milliseconds.
Impressively, the neatly folded drone measures 6.3″ x 6.3″ by 1.4” in size and weighs just over an ounce. When opened, it spans to roughly 2.3” x 2.3” x 1.4”.
“This quick-starting drone, while simple in appearance, is made up of a number of well-thought-out parts. The stiffness of the arms, for example, is critical to the quadrotor’s manoeuvrability. If these parts were flexible, they could bend and vibrate while in flight, causing instability and reducing the quadrotor’s response time to external commands,” the researchers explain. “Stiffness in the arms is a key factor for folding, and by spreading out horizontally the arms avoid imbalances caused by the laws of gravity. There is no need for an additional reinforcing mechanism, which would add to the weight of the device.”
At the moment, the drone must still be folded manually, but it takes less than 10 seconds for someone with practice. The team reveals that this process will be automated in future iterations along with a lighter body and stronger arms to withstand crashes. The principle of origami folding could also be applied to other types of flying devices in the form of wings, a protective cage or other innovations, the researchers claim.
Interested? Read all about the project here.