Fair warning: [Paweł Spychalski]’s video is mostly him talking about how bad his “dualcopter” ended up. There are a few sequences of the ill-fated UAV undergoing flight tests, most of which seem to end with it doing a reasonable impression of a post-hole auger. We have to admit that it’s a pretty poor drone. But one can only truly fail if one fails to have some fun doing it, [Paweł] enjoyed considerable success, at least judging by the glee with which he repeatedly cratered the craft.
The overall idea seems to make sense, with coaxial props mounted in the middle of a circular 3D-printed frame. Mounted below the props are crossed vanes controlled by two servos. The vanes sit in the rotor wash and provide pitch and roll control, while yaw and thrust are controlled by varying the speeds of the counter-rotating props. [Paweł] knew going in that this was a sketchy aerodynamic design, and was surprised it performed as well as it did. But with ground effects limiting roll and pitch control close to the ground, the less-than-adequate thrust due to turbulence between the rotors, and the tendency for the center of mass and the center of gravity to get out whack with each other, all made for a joyously unstable and difficult to control aircraft.
Despite the poor performance, [Paweł] has plans for a Mark II dualrotor, a smaller craft with some changes based on what he learned. He’s no slouch at pushing the limits with multirotors, with 3D-printed racing quad frames and using LoRa for control beyond visual range. Still, we’re sure he’d appreciate constructive criticism in the comments, and we wish him luck with the next one.
Continue reading “Fail of the Week: Two Rotors Are Not Better Than Four”
One of the companion technologies in the developing field of augmented reality is gesture tracking. It’s one thing to put someone in a virtual or augmented world, but without a natural way to interact inside of it the user experience is likely to be limited. Of course, gestures can be used to control things in the real world as well, and to that end [Sarah]’s latest project uses this interesting human interface device to control a drone.
The project uses a Leap Motion sensor to detect and gather the gesture data, and feeds all of that information into LabVIEW. A Parrot AR Drone was chosen for this project because of a robust API that works well with this particular software suite. It seems as though a lot of the grunt work of recognizing gestures and sending commands to the drone are taken care of behind-the-scenes in software, so if you’re looking to do this on your own there’s likely to be quite a bit more work involved. That being said, it’s no small feat to get this to work in the first place and the video below is worth a view.
To some, gestures might seem like a novelty technology with no real applications, but they do have real-world uses for people with disabilities or others with unusual workflow that require a hands-free approach. So far we’ve seen hand gesture technologies that drive cars, help people get around in the physical world, and even play tetris.
Continue reading “Drone Takes Off With a Flick of the Wrist”
With the advancements in quadrotor parts and technology over the years, it’s become possible to make just about anything fly if you can strap some high-speed rotors to it. Introducing the first edible quadrotor!
[Michael] enjoys building and flying quadrotors. His girlfriend enjoys baking and making chocolates. One day she had a crazy idea — what if they made a quadrotor together, combining their unique skill sets? [Michael] was a bit skeptical at first. After all, chocolate doesn’t really compare to aluminum or carbon for a frame material… and chocolate melts at room temperature. Regardless — they were curious enough to try it out and see for sure.
First they built a wooden prototype and then created a silicone mold from it. Using Styrofoam and metal spacers for the electronics mounts they filled the mold with chocolate and let it set. A bit of assembly later and they had a chocolate quadrotor. It flies too.
Continue reading “Chocolate Quadrotor Proves You Can Make Anything Fly”
Inverted Quadcopter? That generally means a crash is soon to follow. Not so for a new crop of quadcopter fliers. These new quadcopters are capable of sustained inverted flight. We’ve seen inverted quadcopters before here on hackaday. However, previous inverted quadcopters always used collective pitch to control the thrust produced by the blades. Collective pitch on a quadcopter is much simpler than it is on the main rotor of a traditional helicopter. R/C and full-scale helicopters mix collective and cyclic pitch to articulate the main rotor blades. A quadcopter only needs the collective portion, which is similar to a traditional helicopters tail rotor mechanism, or a variable pitch prop on an airplane.
These new quadcopters are using a much simpler method of flying inverted: Spin the motors backwards. Quadcopters control their flight by quickly varying the speed of rotation of each motor. Why not completely reverse the motor then? Today’s brushless outrunner motors have more than enough power to quickly reverse direction. The problem becomes one of propellers. Standard propellers are designed to create thrust in one direction only. Every quadcopter uses two clockwise rotation and two counterclockwise rotation propellers. Propellers will generate reverse thrust if they are spun backwards, however they will not be as efficient as they would when spinning the direction they were designed for. The quad fliers have found a partial solution to this problem: Remove the curve from the blade. R/C propeller blades are sold by diameter and blade pitch. The pitch is a measure of the angle of attack of the blades. R/C blades also have an airfoil style curve molded into them. Removing this curve (but not changing the pitch) has helped the problem.
This final problem is control systems. Since quadcopters already are relying on computer control for basic flight, it’s simply a matter of loading custom firmware onto your flight board to support motor rotation reversal. Speed controls also have to be capable of reverse rotation, which means new firmware as well. We’re curious to see how the quadcopter community settles on the control systems for inverted flight. The R/C helicopter community went through several iterations of control systems over the years. At one point they were using “Invert switches” which reversed controls as well as handled the collective pitch changes. As time went on, these switches fell out of favor and are now known as “Crash switches” due to the result of accidentally hitting one while flying, or before engine start.
Continue reading “Quadcopters Go Inverted by Reversing Their Motors”
In recent years, quadrotors have exploded in popularity. They’ve become cheap, durable, and can do some really impressive things, but are they the most efficient design? The University of Queensland doesn’t think so.
Helicopters are still much more efficient and powerful due to their one big rotor, and with the swashplate mechanism, perhaps even more maneuverable — after all did you see our recent post on collective pitch thrust vectoring? And that was a plane! A few quick searches of helicopter tricks and we think you’ll agree.
The new design, which is tentatively called the Y4, or maybe a “Triquad” is still a quadrotor, but it’s been jumbled up a bit, taking the best of both worlds. It has a main prop with a swashplate mechanism, and three smaller rotors fixed at 45 degree angles, that provide the counter torque — It’s kind of like a helicopter with three tails.
Regarding efficiency, the researchers expect this design could achieve an overall increase of about 25% in performance, compared to that of a standard quadrotor. So, they decided to test it and built a quad and a Y4 as similar as possible — the same size, mass, batteries, arms, and controller board. The results? The Y4 had an increased run time of 15%! They think the design could very well make the 25% mark, because in this test study, the Y4 was designed to meet the specifications of the quad, whereas a more refined Y4 without those limitations could perhaps perform even better.
Unfortunately there’s no video we can find, but if you stick around after the break we have a great diagram of how (and why) this design works!
Continue reading “Should all Quadrotors Look like This?”
[Oscar] has been busy lately building DIY mini quadcopters. We saw his controller design earlier in the month. Back then he was using it with his walking robot designs. Now [Oscar] has posted up some information on his quadcopter work. Even though [Oscar] is new to mini quads, he began by designing his own frame. He started his frame design by using a cut down version of the well-known 949 frame. [Oscar] chose polystyrene for his motor mounts, which turned out to be the downfall of the frame. Polystyrene proved to be much too flimsy to handle the vibrations of the motors and props. The vibrations were transmitted to the accelerometers, which resulted in a model that was very hard to control. You can see this in the first video after the break.
For his second attempt, [Oscar] started with a proven design from HobbyKing. HobbyKing’s fiberglass mini quadcopter frame is sturdy, but heavy, and expensive to replace (If the parts are even in stock). The frame did work though, so he used it as a starting point for his second DIY frame. The new frame is based upon fiberglass shafts. [Oscar] used hot glue to join the shafts to the motor mounts. Each joint was wrapped in string, which was then coated with hot glue. We’d suggest thin cyanoacrylate glue in the future for these types of joints. Only a few drops of CA soaks up into the string, creating an extremely light and strong joint. [Oscar’s] frame ended up at about half the weight of the HobbyKing frame, but was stiff enough for a successful flight test, as can be seen in the second video after the break.
Continue reading “DIY Mini Quadcopter Frame is Light and Strong”
[FlorianH] has all kinds of new features to show off with this generation of his quadcopter project. Just about everything has seen an upgrade or some other kind of tweak since we looked in on the last version of the aircraft.
You’ll find some outdoor flight demo clips after the break. Right off the bat we’re impressed at the rock solid stability of the quadrotor while in flight. Even indoors the last version had a hint of a wobble as the control loop calculated stabilization. Here he borrowed some code from the open source Aeroquad project which helps account for this improvement. But the hardware choices lend a hand too. He moved from an ATmega32 up to an STM32F405RG processor. That’s an ARM chip which he programs using one of STM’s Discovery boards. The motors have all been upgraded as well (if you listen in the demo videos for both models you can hear a difference) and he redesigned the frame, which combines carbon tube with 3D printed parts to keep it light yet strong. The upgrade is every bit as impressive as the original build!
Continue reading “[FlorianH] shows off MinimaBL, the next generation of his quadcopter project”