Everyone knows birds descended from dinosaurs, but exactly how that happened is the subject of much study and debate. To help clear things up, these researchers went all out and just straight up built a robotic dinosaur to test their theory: that these proto-birds flapped their “wings” well before they ever flew. Now, this isn’t some hyper-controversial position or anything. It’s pretty reasonable when you think about it: natural selection tends to emphasize existing features rather than invent them from scratch. If these critters had, say, moved from being quadrupedal to being bipedal and had some extra limbs up front, it would make sense that over a few million years those limbs would evolve into something useful. But when did it start, and how? To investigate, Jing-Shan Zhao of Tsinghua University in Beijing looked into an animal called Caudipteryx, a ground-dwelling animal with “feathered forelimbs that could be considered “proto-wings.” Based on the well-preserved fossil record of this bird-dino crossover, the researchers estimated a number of physiological metrics, such as the creature’s top speed and the rhythm with which it would run. From this they could estimate forces on other parts of the body — just as someone studying a human jogger would be able to say that such and such a joint is under this or that amount of stress. What they found was that, in theory, these “natural frequencies” and biophysics of the Caudipteryx’s body would cause its little baby wings to flap up and down in a way suggestive of actual flight. Of course they wouldn’t provide any lift, but this natural rhythm and movement may have been the seed which grew over generations into something greater. To give this theory a bit of practical punch, the researchers then constructed a pair of unusual mechanical items: a pair of replica Caudipteryx wings for a juvenile ostrich to wear, and a robotic dinosaur that imitated the original’s gait. A bit fanciful, sure — but why shouldn’t science get a little crazy now and then? In the case of the ostrich backpack, they literally just built a replica of the dino-wings and attached it to the bird, then had the bird run. Sensors on board the device verified what the researchers observed: that the wings flapped naturally as a result of the body’s motion and vibrations from the feet impacting the ground. The robot is a life-size reconstruction based on a complete fossil of the animal, made of 3D-printed parts, to which the ostrich’s fantasy wings could also be affixed. The researchers’ theoretical model predicted that the flapping would be most pronounced as the speed of the bird approached 2.31 meters per second — and that’s just what they observed in the stationary model imitating gaits corresponding to various running speeds. You can see another gif . As the researchers summarize: These analyses suggest that the impetus of the evolution of powered flight in the theropod lineage that lead to Aves may have been an entirely natural phenomenon produced by bipedal motion in the presence of feathered forelimbs. Just how legit is this? Well, I’m not a paleontologist. And an ostrich isn’t a Caudipteryx. And the robot isn’t exactly convincing to look at. We’ll let the scholarly community pass judgment on this paper and its evidence (don’t worry, it’s been peer-reviewed), but I think it’s fantastic that the researchers took this route to test their theory. A few years ago this kind of thing would have been far more difficult to do, and although it seems a little silly when you watch it (especially in gif form), there’s a lot to be said for this kind of real-life tinkering when so much of science is occurring in computer simulations. The paper was .
Drones are useful in countless ways, but that usefulness is often limited by the time they can stay in the air. Shouldn’t drones be able to take a load off too? With these special claws attached, they can perch or hang with ease, conserving battery power and vastly extending their flight time. The claws, created by a highly multinational team of researchers I’ll list at the end, are inspired by birds and bats. The team noted that many flying animals have specially adapted feet or claws suited to attaching the creature to its favored surface. Sometimes they sit, sometimes they hang, sometimes they just kind of lean on it and don’t have to flap as hard. As the researchers write: In all of these cases, some suitably shaped part of the animal’s foot interacts with a structure in the environment and facilitates that less lift needs to be generated or that power flight can be completely suspended. Our goal is to use the same concept, which is commonly referred to as “perching,” for UAVs [unmanned aerial vehicles]. “Perching,” you say? Go on… We designed a modularized and actuated landing gear framework for rotary-wing UAVs consisting of an actuated gripper module and a set of contact modules that are mounted on the gripper’s fingers. This modularization substantially increased the range of possible structures that can be exploited for perching and resting as compared with avian-inspired grippers. Instead of trying to build one complex mechanism, like a pair of articulating feet, the team gave the drones a set of specially shaped 3D-printed static modules and one big gripper. The drone surveys its surroundings using lidar or some other depth-aware sensor. This lets it characterize surfaces nearby and match those to a library of examples that it knows it can rest on. Squared-off edges like those on the top right can be rested on as in A, while a pole can be balanced on as in B. If the drone sees and needs to rest on a pole, it can grab it from above. If it’s a horizontal bar, it can grip it and hang below, flipping up again when necessary. If it’s a ledge, it can use a little cutout to steady itself against the corner, letting it shut off or all its motors. These modules can easily be swapped out or modified depending on the mission. I have to say the whole thing actually seems to work remarkably well for a prototype. The hard part appears to be the recognition of useful surfaces and the precise positioning required to land on them properly. But it’s useful enough — in professional and military applications especially, one suspects — that it seems likely to be a common feature in a few years. The paper describing this system was . I don’t want to leave anyone out, so it’s by: Kaiyu Hang, Ximin Lyu, Haoran Song, Johannes A. Stork , Aaron M. Dollar, Danica Kragic and Fu Zhang, from Yale, the Hong Kong University of Science and Technology, the University of Hong Kong, and the KTH Royal Institute of Technology.