Tag Archives: EPFL

These palm-sized drones can unfold and deploy in half a second

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.

Pleurobot is a lifelike robotic salamander

This bio-inspired robot may be the future of search-and-rescue missions.

Bio-inspired robotic locomotion is a fairly new sub-category of bio-inspired design, revolving around learning concepts from nature and applying them to the design of real world engineered systems. More specifically, this field is about making robots that are inspired by biological systems. When it comes to these bio-mimicking bots, it seems as though we’ve seen just about everything, ranging from bats to spiders to dogs. And while it may not be all that difficult to make a bot that looks like an animal, having it behave like one is an entirely different story.


Meet Pleurobot. Recently developed by the BioRob at EPFL and NCCR Robotics, it is a salamander-inspired robot that is truly amphibious, meaning it is capable of walking, changing its gait to navigate uneven terrain, and even swimming. As the researchers note, the key to Pleurobot’s eerily-lifelike motion is its unique design, which was based on 3D X-ray movies of a real salamander walking, waddling and swimming. By tracking up to 64 points on the animal’s skeleton, the team was able to record movements of bones, and then deduce the number and position of active and passive joints needed for the robot to reproduce the 3D movements with reasonable accuracy.

According to its research proposal, the team first created a snake robot Kulko with tactile sensors in order to test the suggested control framework. This was comprised of a serial connection of 10 identical ball-shaped joint modules, along with a smooth surface to avoid getting stuck against obstacles. Each of the joint modules had 2-degrees of freedom (pitch and yaw), and had used servo motors as its actuators. On each side of every joint module, there were four force sensing resistors tasked with measuring contact forces — these were the only contact points between outer shell and inner structure.

“The current layout of the sensors can only measure horizontal forces which is enough for the application. The total force is estimated by summing forces measured by each FSR on the module. Each module also contains two Lithium-Ion batteries, angle sensors (magnetic rotary encoders), voltage regulation card, battery charger card and microcontroller card. The microcontroller card is based on the Atmel microcontroller AT90CAN128 and is continuously measuring position of the motors and controlling them with a PWM signal. Modules communicate with each other over CAN bus,” BioRob’s Tomislav Horvat writes.


By design, Pleurobot provides torque control for all the active joints, which enabled its creators to apply their neural network models of the spinal cord neural circuits of the salamander and to activate virtual muscles to replicate the recorded animal movements along with realistic viscoelastic properties. This was imperative when obtaining a fundamental understanding of vertebrate motor control.

What’s more, Pleurobot is also waterproof. While this feature actually proved to be the project’s most daunting assignment, the salamander-like project is currently using a water-repellant skin suit. Moving forward, the team hopes to improve upon this layer with aspirations that one day, the bio-mimicking robot will have a role in search-and-rescue efforts, with shallow waters for example. Its amphibious nature will enable it to go where humans cannot.

In the future, the team says it plans to use Pleurobot’s design methodology to bring early tetrapods to ‘life.’ So sure, we can write about it all day, but watching it in action is so much better! Those wishing to read up on the bio-mimicking project can download the team’s detailed proposal here, or head over to its official page for an abbreviated version.