As useful as old-fashioned fixed-wing and quadrotor drones have become, they still tend to be reasonably complicated, expensive machines that you really desire to be able to use more than once. When a one-way trip is all that you have in mind, you want something simple, reliable, and cheap, and we’ve seen a bunch of various designs for drone gliders that more or less fulfill those criteria.
 
For an even easier gliding design, you want to minimize both airframe mass and control surfaces, and the maple tree supplies some inspiration in the form of samara, those unique seed pods that whirl to the ground in the fall. Samara are really just an unbalanced wing that spins, and while the natural ones don’t steer, adding an actuated flap to the robotic version and moving it at just the right time results in enough controllability to aim for a specific point on the ground.
 
Roboticists at the Singapore University of Technology and Design (SUTD) have been playing with samara-inspired drones, and in a new paper in IEEE Robotics and Automation Letters they explore what happens if you attach five of the drones together and then divide them in mid air.
 
Basically, a samara design acts as a decelerator for an aerial payload. You can think of it like a parachute: It makes sure that whatever you toss out of an airplane gets to the ground intact rather than just smashing itself to bits on impact. Steering is possible, but you don’t get a lot of stability or precision control. The RA-L paper details one solution to this, which is to collaboratively use five drones at once in a configuration that looks a bit like a helicopter rotor.
And once the multi-drone is right where you want it, the five individual samara drones can split off all at once, heading out on their own missions. It's quite a sight.
 
The samara autorotating wing drones themselves could understandably carry small payloads like sensors or emergency medical supplies, with these small-scale versions able to handle an extra 30 grams of payload. While they might not have as much capacity as a traditional fixed-wing glider, they have the advantage of being able to descent vertically, and can perform better than a parachute due to their ability to steer. The experts plan on improving the design of their little drones, with the goal of improving the rotation speed and improving the control performance of both the individual drones and the multi-wing collaborative version.



This article is originally posted on Tronserve.com