Drones, unmanned aerial vehicles (UAVs), have risen in popularity in recent years thanks to their usefulness. They have come in handy for things such as bridge inspections and construction surveys, to agricultural monitoring and real-estate photography. For now, drone applications are mostly for outdoor scenarios where there is plenty of room for a flying craft to maneuver.
The future of drones brings the drones indoors. Researchers and engineers are currently working out ways that drones could be used within confined spaces, for example, to carry out surveys inside caves, or search and rescue operations in collapsed buildings. Why drones haven’t been able to do this yet is because motion in these confined spaces often involves travelling through small cracks or gaps, a task that is difficult or impossible for a conventional drone with a fixed size and configuration.
What researchers and drone designers are doing to address this challenge is very interesting. They are pulling their inspiration from nature. They are investigating how best to mimic the way birds navigate around obstacles and through small openings – by morphing their shape, folding up or tucking in their wings. They want to translate these capabilities into the drones to enable them to slip into areas they would otherwise be unable to enter.
The creations they have come up with are really amazing! Check out these prototypes below for a sneak peek into the latest research of shape-changing aerial drones:
The “Quad-morphing” Robot
This drone was developed by researchers at Aix-Marseille Université in France. It is a quadrotor drone with four propellers. It consists of a central bar with two propeller arms attached to it and one propeller fixed to each end of the two bars (4 propellers in all).
The arms are rigged with wires that wrap around a pulley system in the center of the drone. This system is mounted onto a servomotor that can rapidly change the angle of the propeller arms by either pulling them in to align with the axis of the central bar or force them out so that the arms are perpendicular to the bar and the propellers are spread wide.
When the arms are pulled in, the robot can easily slip through narrow gaps; but it loses lift as the propellers overlap the central bar. In this position, it cannot fly well. Once the robot has cleared the obstacle, the arms have to swing back out to stabilize the drone.
The Foldable Drone
This drone was developed by researchers from the University of Zurich and Ecole Polytechnique Federale de Lausanne in Switzerland. They came up with a more flexible version of the quadrotor drone. It consists of four arms extending from a central body with a propeller mounted at the end (4 in total). The central body houses a battery, and the sensing and control systems.
With this system, each arm can fold inward toward the body independently, allowing the drone to assume various shapes. These shapes include:
- A narrow ‘H’ configuration allows the drone to fit through vertical gaps. In this configuration, the drone can also grasp and carry objects using two arms as a clamp to grip objects.
- A ‘T’ configuration enables it to approach vertical surfaces for close-up inspection.
- A fully folded ‘O’ configuration is the drone in it’s smallest size – when folded up like this, the vehicle can fit through tight openings but loses efficiency and maneuverability.
- The default expanded ‘X’ configuration is the one in which the drone maximizes flight time and agility.
This drone was developed by University of Tokyo researchers. It is similar to the previous two quadrotors in the sense that it has four propellers, otherwise, it is quite different. It consists of a string of four links arranged in a linear series. A propeller is attached to each link. At the joint where each link meets there are hinges that enable rotation in two dimensions.
When it is flying, extended to its full length, the links form a straight line of flying propellers. Although, it can bend into a variety of shapes from a squiggly line to a perfect square. This capability can be used to manipulate objects by wrapping its body around them to grasp, pick up, carry and drop them at different locations.
This drone was also created by University of Tokyo researchers. The name DRAGON is short for Dual-Rotor embedded multilink robot with the Ability of multi-deGree-of-freedom aerial transformatiON. It is similar to the previous drone in the sense that its snake-like structure is composed of four links, but it has an even more ambitious and unconventional design regarding its transformational abilities.
These abilities surpass those of all other drones created yet. Their hinged joints between links allow servomotor-powered actuation in both the x-y and x-z planes, as well as gimbaled thrusters that can be adjusted in both roll and pitch. A dual-rotor gimbal module carrying two ducted fan thrusters is attached to the center of each link, for a total of eight thrusters providing finely controlled directional propulsion.
Its aerial transformation capabilities include a wide range of shapes, from simple straight lines and squares to three-dimensional spirals. If a drone that can fly around shaped like a spiral isn’t impressive enough, its surprising aerial maneuverability will definitely amaze you. In one flight experiment, they explain how the robot was able to traverse a horizontal gap, beginning the maneuver hovering in a coiled position below the opening and unfolding into a snaking helix as it movewww.youtube.com/watch?v=through the gap.