Fixed-wing planes and helicopters are no longer the darling of the RC world. Even quadcopters and other multirotors are starting to look old hat, as the community looks to ever more outrageous designs. [rctestflight] has slimmed things down to the extreme with this coaxial bicopter build, also known as the Flying Stick (Youtube video, embedded below).
The initial design consists of two brushless outrunner motors fitted with props, rotating in opposite directions to cancel out their respective torques. Each is mounted on a gimbal, setup to provide control authority. iNav is used as a flight controller, chosen due to its versatile motor mixing settings. The craft was built to test its ability at recovery from freefall, as a follow-on from earlier attempts at building a brushless “rocket” craft.
Performance is surprisingly good for what is fundamentally two props on a stick. Initial tests didn’t quite manage a successful recovery, but the repaired single-gimbal version almost achieves the feat. Multirotors in general struggle with freefall recovery, so more research in this area is definitely worthwhile. Video after the break.
Continue reading “Flying Sticks Are Now A Thing”
Bees. The punchline to the title is bees carrying sensors like little baby bee backpacks. We would run out of fingers counting the robots which emulate naturally evolved creatures, but we believe there is a lot of merit to pirating natural designs, but researchers at the University of Washington cut out the middle-man and put their sensors right on living creatures. They measured how much a bee could lift, approximately 105 milligrams, then built a sensor array lighter than that. Naturally, batteries are holding back the design, and the rechargeable lithium-ion is more than half of the weight.
When you swap out brushless motors for organics, you gain and lose some things. You lose the real-time control, but you increase the runtime. You lose the noise, but you also lose the speed. You increase the range, but you probably wind up visiting the same field over and over. If your goal is to monitor the conditions of flowering crops, you may be ready to buy and install, but for the rest of us, dogs are great for carrying electronics. Oh yes. Cats are not so keen. Oh no.
[Klaus Halbach] gets his name attached to these clever arrangements of permanent magnets but the effect was discovered by [John C. Mallinson]. Mallinson array sounds good too, but what’s in a name? A Halbach array consists of permanent magnets with their poles rotated relative to each other. Depending on how they’re rotated, you can create some useful patterns in the overall magnetic field.
Over at the K&J Magnetics blog, they dig into the effects and power of these arrays in the linear form and the circular form. The Halbach effect may not be a common topic over dinner, but the arrays are appearing in some of the best tech including maglev trains, hoverboards (that don’t ride on rubber wheels), and the particle accelerators they were designed for.
Once aligned, these arrays sculpt a magnetic field. The field can be one-sided, neutralized at one point, and metal filings are used to demonstrate the shape of these fields in a quick video. In the video after the break, a powerful magnetic field is built but when a rare earth magnet is placed in the center, rather than blasting into one of the nearby magnets, it wobbles lazily.
Be careful when working with powerful magnets, they can pinch and crush, but go ahead and build your own levitating flyer or if you came for hoverboards, check out this hoverboard built with gardening tools.
Continue reading “Step The Halbach From My Magnets”
Flying is an energy-intensive activity. The birds and the bees don’t hover around incessantly like your little sister’s quadcopter. They flit to and fro, perching on branches and leaves while they plan their next move. Sure, a quadcopter can land on the ground, but then it has to spend more energy getting back to altitude. Researchers at Harvard decided to try to develop flying robots that can perch on various surfaces like insects can.
Perching on surfaces happens electrostatically. The team used an electrode patch with a foam mounting to the robot. This allows the patch to make contact with surfaces easily even if the approach is a few degrees off. This is particularly important for a tiny robot that is easily affected by even the slightest air draft. The robots were designed to be as light as possible — just 84mg — as the electrostatic force is not particularly strong.
It’s estimated that perching electrostatically for a robot of this size uses approximately 1000 times less power than during flight. This would be of great use for surveillance robots that could take up a vantage point at altitude without having to continually expend a great deal of energy to stay airborne. The abstract of the research paper notes that this method of perching was successful on wood, glass, and a leaf. It appears testing was done with tethers; it would be interesting to see if this technique would be powerful enough for a robot that carries its own power source. Makes us wonder if we ever ended up with tiny flyers that recharge from power lines?
We’re seeing more tiny flying robots every day now – the IMAV 2016 competition was a great example of the current state of the art.
Continue reading “Tiny Robot Clings To Leaves With Static Electricity”
The types of steps and missteps the Wright brothers took in developing the first practical airplane should be familiar to hackers. They started with a simple kite design and painstakingly added only a few features at a time, testing each, and discarding some. The airfoil data they had was wrong and they had to make their own wind tunnel to produce their own data. Unable to find motor manufacturers willing to do a one-off to their specifications, they had to make their own.
Sound familiar? Here’s a trip through the Wright brothers development of the first practical airplane.
Continue reading “Why The Wright Brothers Succeeded”
In case you haven’t seen it yet, this video has been taking the internet by storm. The YouTube user [Gasturbine101] has successfully taken flight in his home made multi-rotor flying machine.
It’s a massive array of high powered brushless motors with props, fifty-four in fact, all counter-rotating. It has a weight of 148kg (we assume this includes the inventor), and produces a maximum lift of 164kg. Apparently it’ll even last for about 10 minutes. The props are grouped into six, using Hobbyking stabilizers to balance the flight.
He calls it the Swarm.
Continue reading “Being Picked Up By A Swarm Of Drones May Become Reality”
Turns out you don’t have to be a multi-million dollar corporation like Festo to create a remote controlled, flapping bird robot. [Kazuhiko Kakuta] is a medical Doctor of Allergy, and in his free time he likes to build flying mechanical birds with his son.
It has just over a meter wingspan, weighs 193 grams, and it flies by flapping its wings. The majority of its components are 3D printed. If that’s not impressive enough for you as is, consider this. It it has no sensors, no gyroscopes or anything — it’s all manually controlled by [Kazuhiko].
And this isn’t even the only ornithopter he’s done. He’s also created something out of an anime film, Castle in the Sky. He even sells the designs for one of them, to be printed via Shapeways.
Continue reading “Mechanical Bird Actually Flies By Flapping Its Wings”