Robots have traditionally been designed with a specific purpose to perform one very specific task, but researchers from Beihang University are taking an entirely different approach with New robotic drone It can operate underwater just as easily in the air, and features a clever nature-inspired trick to increase its range.
When you think of robots, one of two versions likely come to mind: the highly capable humans promised by science fiction, or the reckless, articulated arms that perform repetitive tasks in factories. The latter approach is somewhat of what we’ve been in for decades, but as technology slowly catches up with the imaginations of science fiction authors, robotics designers have begun developing mechanisms capable of performing a variety of actions. Boston Dynamics spotHe, for example, uses four dog-like legs to navigate diverse terrain and perform many different tasks, including protecting the ruins of Pompeii overnight and creating detailed 3D maps of areas that are difficult for humans to visit.
An adaptive approach makes it easier for companies or research institutions to justify the high cost of the robot, but what the Beihang University Biomechanics Laboratory and the Soft Robotics Laboratory have created is truly unique. Even with highly articulated legs, Boston Dynamics is still limited to missions on the ground. This new drone can perform missions either underwater, in the air, or both, with no modifications required in between.
For most quadcopters, landing on water means the pilot will have to go out to rescue them (and then replace most of their electronic components). This plane is different. It is completely waterproof and features a set of self-folding propellers that collapse when operating at low underwater speeds to efficiently maneuver the drone when submerged. Then it extends automatically when the drone moves out of the water and into the air. The researchers optimized the performance of the drone so that the transition from water to air takes about a third of a second, and like a group of dolphins that jump out of water, the drone is able to repeat transitions between water and air, performing seven of them in a row during testing in about 20 a second.
As with any electronic device, a robot’s autonomous capabilities are often limited by the capacity of its batteries, and that’s especially the case for flying drones that rely on four electric motors constantly spinning to stay aloft. In laboratory settings, you’ll often see advanced robots attached to cable tethers that provide a non-stop source of power, but that’s not a great option for bots designed to explore the ocean depths or collect aerial data—or both, in this case.
To dramatically increase the range of this drone, and to help conserve battery power while traveling to and from a mission site, the researchers gave it an additional upgrade inspired by the remora fish, better known as the suckerfish, which uses an adhesive disc on top of its head to temporarily attach itself to other underwater creatures in order to hitch a ride and conserve energy.
Drones that can land in order to carry out targeted observations while preserving battery life are not a new idea, but like robots in a factory, they typically use mechanisms tailored for specific surfaces, like articulated claws holding a branch Or sticky, gecko-inspired feet that stick to walls. For a robotic drone designed with flexibility in mind, the researchers wanted a more versatile way to attach to a variety of surfaces: wet, dry, smooth, rough, curved, or even those that move underwater, where the shear forces of water require grip. Too powerful.
Remora’s adhesive disc was the perfect solution, as it includes a built-in overhang that allows it to remain adherent to surfaces even with partial contact. Two years ago, Li Wen, one of the researchers and author of the paper released today, was part of another research project at Beihang University that reverse-engineered how remora discus actually works.
This research revealed that remora fish stick to surfaces just like a suction cup, with a flexible oval edge of soft tissue that creates an airtight seal. When water is squeezed out of the gap between the remora and its host, the suction keeps it in place. The surface of a remora’s disc is also covered with edges lined up in columns and rows called lamellae (similar to the bumps you can feel on the roof of your mouth) that can be stretched by muscle contractions to engage the small tendons that hold more of the upper part of the mouth. Host. These lamellar flanges also help create smaller suction compartments that keep them sealed even if the larger lip of the disc doesn’t. Unlike a suction cup, which releases its grip on a smooth surface when a small part of its edge is lifted, a remora will hold up.
The team was able to create a synthetic version of the suction disc of the remora through a four-layer approach. They’ve paired a super-elastic layer on top with stiffer structures underneath, as well as a layer with a network of tiny channels that can be inflated when pumped full of liquid, replacing live muscle tissue as a way to engage lamellar structures to increase suction.
The suction mechanism mounted above the submersible plane allows it to adhere to a variety of surfaces, even if they are rough to the touch, not completely flat, or have a smaller surface area than the suction mechanism. Like a remora, the drone could, at least in theory, find itself an underwater host (not immediately afraid of its rotating propellers) and suspend itself in free flight, requiring only the suction mechanism to operate, and the minimal drain on the batteries on board. The same can be done in the air, although the challenges of successfully attaching a drone to another aircraft would be formidable, even something as slow as a glider has a minimum speed of 40 mph: a difficult moving target.
The most reasonable use of the suction mechanism is as a way to temporarily position the drone somewhere with an ideal vantage point for long-range observations. Instead of relying on its four motors to maintain a specific position underwater while fighting moving currents, the drone can stick to a stone or piece of wood and shut off its motors, while still operating its sensors and cameras. The same can be done above the water line, flying the drone up and sticking to the side of a tall building or the underside of a wind turbine nacelle, taking measurements and collecting other data without using its battery-draining motors. It’s a battery technology solution that’s still incredibly limited and avoids the need to repair the batteries themselves.