Have you ever noticed a flying beetle fall to the ground? Well, you might have! What you might not have seen is its ability to self-right itself.
Researchers took inspiration from this same approach to create the first self-righting winged drone- Ely.
The inspiration behind the super drone buggy
A real beetle inspires this flying robot. How? Let’s see.
Ladybugs have a pair of forewings called elytra. They use these wings to self-right themselves in case of a fall. Drones encounter falling in humanless terrains, making it very important for them to get back to flying without any external help.
Inspired by the ladybugs, Scientists have created artificial elytra, which help these drones self-right themselves in a second.
The super drone can flip back by moving the wings backward and then directing them 180 degrees forward, just like a ladybug. Charalampos Vourtsis, a doctoral assistant at the Laboratory of Intelligent Systems, Ecole Polytechnique Federale de Lausanne in Switzerland, co-created the design.
The aerodynamic efficiency of the super drone buggy
One challenge that Scientists faced was maintaining the aerodynamics efficiency while adding the self-righting feature. A specific geometry of the super drone serves this purpose.
The drone has a forewing called the elytra and a hind wing with a body of around 55cm long. This design is a replica of the original wing design of the ladybug. The elytra lie on a fixed-wing platform named Ely.
The drone’s weight also had to be kept in check so that the aerodynamic performance doesn’t get compromised. For this purpose, scientists used certain materials to build the drone and optimized the distance between the elytra and hind wings.
The drone’s wings are fixed, unlike the real beetle that flaps both its wings. So it becomes essential to align the wings at the aerodynamic center of the drone’s body for functional simplicity.
Hybrid carbon fiber and Kevlar composite fabric contribute to the lightweight of the elytra. Expanded Polypropylene (EPP) is used to make the hind wings. These materials make the drone tough and sustainable in different terrains.
As actual bugs inspire the drone, the elytron has a shell-like ogive design resembling the beetle wings. The dimensions are also taken from the real beetle and scaled to meet the standard MAV proportions.
For maintaining the aerodynamics performance, researchers found that the length of the elytra played a considerable role. They found that the larger the elytra, the faster the self-righting is. This is because the elytra generate a specific torque directly related to the distance of the applied force.
After experimenting with three different lengths, they found that 17 cm long elytra perform better at self-righting for any amount of torque produced. On a plain surface, the longer length yielded better results than the shorter one. The drones could also self-right themselves when the elytra are longer. So they tested it on different inclines of 10°, 20°, and 30°.
The mechanism behind this self-righting super drone
A common self-righting technique used for terrestrial robots is the use of long projection. Those projections take the help of actuators to achieve the torque required for self-righting themselves.
But in flying bots, the main problem is that the projections allow the robots to self-right themselves, but the performance decreases. As discussed above, The Super Drone Buggy’s design solves this problem. This drone has an extra pair of wings called elytra that helps the drone self-right itself without decreasing the aerodynamic efficiency.
Coming back to the self-righting technique, A real beetle uses elytra to balance itself while producing the torque needed for self-righting with its legs or hind wings. The super drone works on the exact mechanism. But instead of legs, scientists used the connected actuators to produce the torque and flip over.
When the drone falls, the elytra pitches 90degree and then back to 180degree forward, which rotates the drone around its lateral axis, flipping over. An onboard microcontroller controls this movement. Once done, the elytra move back to its initial flying position, and the drone is ready to take off again.
Can this change how drones work
What makes the ‘super drone’ powerful is its ability to self-right itself in various terrains for different fall positions.
The ‘Super Drone Buggy’ was tested on different surfaces, including fine sand, rocks, shells, pavement, coarse sand, wood chips, and grass. The drones could self-right themselves perfectly in almost all situations, except for grass and fine sand.
This comes as a significant advancement as many drones are needed to function for different applications. The feature to self-right itself without reducing its aerodynamic efficiency can help them operate across different conditions to enhance its overall performance.
The elytra are still optimized for further improvements to help drones work in the most challenging situations and safely land themselves.
With the advancement of flying bots, Scientists have started finding drone inspirations from wildlife due to their natural survival response.
Bio-inspired drones have been growing in popularity over the last few years.
The Super Drone Buggy can be a great up-gradation to the present nature-inspired drones. The self-righting feature makes the entire performance much more powerful. The materials used are widely available, and their geometry doesn’t compromise the aerodynamic performance.
Interestingly, the system’s ability to fit in aerial and terrestrial, and marine robots can change the way drones work today.