Hackaday Prize Entry: Electric Variable Pitch Props

April 3, 2017 by Brian Benchoff 39 Comments

Barring the smallest manned airplanes, most aircraft that are pulled around by a prop have variable pitch propellers. The reason for this is simple efficiency. Internal combustion engines are most efficient at a specific RPM, and instead of giving the engine more gas to speed up, pilots can simply change the pitch of a propeller. With a gas powered engine, the mechanics and design of variable pitch propellers are well understood and haven’t really changed much in decades. Adding variable pitch props to something pulled around by an electric motor is another matter entirely. That’s what [Peter McCloud] is building for his entry to the Hackaday Prize, and it’s going into the coolest project imaginable.

This project is designed for a previous Hackaday Prize entry, and the only 2014 Hackaday Prize entry that hasn’t killed anyone yet. Goliath is a quadcopter powered by a lawnmower engine, and while it will hover in [Peter]’s test rig, he’s not getting the lift he expected and the control system needs work. There are two possible solutions to the problem of controlling the decapatron: an ingenious application of gimballed grid fins, or variable pitch rotors. [Peter] doesn’t know if either solution will work, so he’s working on both solutions in parallel.

[Peter]’s variable pitch rotor system is basically an electronic prop mount that connects directly to the driven shafts on his gas-powered quadcopter. To get power to the electronics, [Peter] is mounting permanent magnets to the quad’s frame, pulling power from coils in the rotor hub, and rectifying it to DC to drive the servos and electronics. Control of the props will be done wirelessly through an ESP32 microcontroller.

Variable pitch props are the standard for everything from puddle jumpers to acrobatic RC helis. In the quadcopter world, variable pitch props are at best a footnote. The MIT ACL lab has done something like this, but perhaps the best comparison to what [Peter] is doing is the incredible Stingray 500 quad. Flite Test did a great overview of this quad (YouTube), and it’s extremely similar to a future version of the Goliath. A big motor (in the Stingray’s case, a brushless motor) powers all the props via a belt, and the pitch of the props is controlled by four servos. The maneuverability of these variable pitch quads is unbelievable, but since the Goliath is so big and has so much mass, it’s doubtful [Peter] will be doing flips and rolls with his quads.

You can check out a video of [Peter]’s build below.

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Flexible Quadcopter Is Nearly Indestructible

March 18, 2017 by Will Sweatman 20 Comments

We’ve all crashed quadcopters. It’s almost inevitable. Everything is going along fine and dandy ’till mother nature opens her big mouth a blows a nasty gust of wind right at you, pushing your quad into the side of a wall. A wall that happens to be composed of a material that is quite a bit harder than your quadcopter. “What if…” you ask yourself while picking up the pieces of you shiny new quad off the ground… “they made these things out of flexible material?”

Well, it would appear someone has done just that. The crash resistant quadcopter is composed of a flexible frame (obviously) which is held rigid with magnets. So the frame works just like the frame of your average quad. Until you crash it, of course. Then it becomes flexible.

The idea came from the wing of a wasp, which you can apparently crumple without damaging it. Be sure to check out the video below of the drone showing off its flexible frame, and let us know if you’ve seen any other types of flexible frame drones in the wild.

Thanks to [JDHE] for the tip!

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Welcome To The Drone Wars

March 18, 2017 by Elliot Williams 18 Comments

“DroneClash” is a competition to be held on December 4th (save the date!) in a hangar at Valkenburg airfield in the Netherlands. The game? Teams try to destroy each others’ quadcopters, navigate through a “Hallway of Doom, Death, and Destruction”, and finally enter a final phase of the game where they try to defend their “queen” drone while taking out those of their opponents.

This sounds like crazy and reckless fun. Surprisingly, it’s being sponsored by the Technical University of Delft’s Micro Air Vehicle (MAV) lab. The goal is to enable a future of responsible drone use by having the ability “to take them out if necessary”.

Drone development has grown hugely in recent years, and you can see the anti-drone industry growing too. Ideally, these developments keep each other in check and result in a safe and responsible incorporation of drones in our daily lives. We are organising DroneClash to generate new ideas in order to encourage this process.

We do have to ask ourselves why anyone would want to use another quadcopter to take out illegally operated quadcopters — there must be a million more effective means from a policing standpoint. On the other hand, if we were re-shooting “Hackers” right now, and looking for a futuristic sport, we would swap out rollerblading for drone combat. Registration opens this week. Gentlebots, start your engines.

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Autonomous Delivery And The Last 100 Feet

March 13, 2017 by Dan Maloney 36 Comments

You’ve no doubt by now seen Boston Dynamics latest “we’re living in the future” robotic creation, dubbed Handle. [Mike Szczys] recently covered the more-or-less-official company unveiling of Handle, the hybrid bipedal-wheeled robot that can handle smooth or rugged terrain and can even jump when it has to, all while remaining balanced and apparently handling up to 100 pounds of cargo with its arms. It’s absolutely sci-fi.

[Mike] closed his post with a quip about seeing “Handle wheeling down the street placing smile-adorned boxes on each stoop.” I’ve recently written about autonomous delivery, covering both autonomous freight as the ‘killer app’ for self-driving vehicles and the security issues posed by autonomous delivery. Now I want to look at where anthropoid robots might fit in the supply chain, and how likely it’ll be to see something like Handle taking over the last hundred feet from delivery truck to your door.

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I’m BatBot

February 3, 2017 by Pedro Umbelino 10 Comments

How would you like a bat bot for your next pet drone? Researchers from the University of Illinois at Urbana-Champaign’s Coordinated Science Laboratory and from the California Institute of Technology, created a bat drone. This is not your regular drone; it’s not a styrofoam, bat-shaped, four-propeller kind of drone. It’s a drone that mimics not only the shape but the movement of the bats wings to achieve flight.

The biomimetic robotic platform, dubbed Bat Bot B2, is an autonomous flying robot. The wing mechanics are controlled by a brushless DC motor for the wing flapping along with four wings actuators to provide linear motion that allows the wings to further change shape in flight. The wings are made of a 56-micron, silicone-based membrane (thinner than an average condom), which for sure helps with their elasticity as well as reducing overall weight, which is only 93 grams.

The bat has only made twenty flights so far, ranging up to 30 meters with some rough landings. It’s not much yet, but the prototype looks pretty slick. We covered another bat bot back in 2012 but the original information is no longer available, and we don’t know what happened to that project. There was also no video. In contrast, you can watch Bat Bot B2 glide.

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Cheap DIY FPV Micro-Drone

January 31, 2017 by James Hobson 28 Comments

FPV drones are a fun but often costly hobby for beginners. Opting for a smaller drone will reduce the chance of damaging the drone when one invariably crashes and the smaller props are also a lot safer if there are any innocent bystanders. YouTuber and Instructables user [Constructed] wanted a cheap FPV capable drone that they could comfortably fly in-and-out of doors, so of course they built their own.

Once the drone’s frame was 3D printed, the most complex part about soldering four small-yet-powerful 8.5 mm motors to the Micro Scisky control board is ensuring that you attach them in the correct configuration and triple-checking them. A quick reshuffling of the battery connections and mounting the FPV camera all but completed the hardware side of the build.

Before plugging your flight controller into your PC to program, [Constructed] warns that the battery must be disconnected unless you want to fry your board. Otherwise, flashing the board and programming it simply requires patience and a lot of saving your work. Once that’s done and you’ve paired everything together, the sky — or ceiling — is the limit!

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Frankenquad Takes To The Air

January 25, 2017 by Adam Fabio 14 Comments

Modern quadcopter flight controllers perform a delicate dance of balancing pitch, yaw, bank, and throttle. They can do this thanks to modern MEMS gyros and accelerometers. The job is easy when the motors, propellers and speed controllers are relatively well matched. But what if they’re not? That’s the questions [SkitzoFPV] set out to answer by building Frankenquad. Frankenquad is a 250 sized FPV quadcopter with 4 different motors and 4 different propellers. The props are different sizes from different manufacturers, and even include a mix of 3 and 4 blade units. If all that wasn’t enough [SkitzoFPV] used 3 different electronic speed controller. Each speed controller has a micro running different firmware, meaning it will respond slightly differently to throttle inputs.

Keeping all this in check was [SkitzoFPV’s] branded version of the Raceflight Revolt R4 flight controller. The Revolt is powered by an STM32F4 series ARM microcontroller. Most of these controllers run variants of the cleanflight open source flight control software. The question was – would it be able to handle the unbalanced thrust and torque of 4 different power combinations?

The flight tests proved the answer was a resounding yes. The quad hovered easily. As the video shows [SkitzoFPV] went on to burn a few holes in the sky with it. Admittedly [SkitzoFPV] is a much better pilot than any of us. He did notice a bit of a bobble and a definite yaw toward the smaller propeller. Still, it’s rather amazing how easily a modern flight controller was able to turn a pile of junk-box components into a flying quadcopter. You can learn more about flight controllers right here.

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