Flight For Your Right (And Do It By Friday)

Model aircraft

About a month ago, the FAA – the governing body for nearly everything that flies in US airspace – proposed an interpretation of their rules governing model aircraft. The world hasn’t ended quite yet, but if the proposed rules go into effect, an entire hobby will be destroyed in the United States. While congress has given the FAA authority over nearly everything that flies, there are specific laws saying what the FAA has no jurisdiction over – model aircraft being one of the major exceptions.

Congress, however, is working on a definition of model aircraft that is at least 10 years out of date and doesn’t have any leeway for the huge advances in technology that have happened since then. Specifically, all FPV flight with video goggles would be banned under the proposed FAA rules. Also, because model aircraft are defined as being for, ‘hobby or recreational purposes,’ anyone who flies a model aircraft for money – a manufacturer conducting flight tests on a new piece of equipment, or even anyone who records a video of their flight, uploads it to YouTube, and hits the ‘monetize’ button – would be breaking the law.

The proposed FAA rules for model aircraft are not in effect yet, and you can still make a public comment on the proposal until 11:59 PM EDT Friday. If you leave a comment, please make a well-reasoned statement on why the FAA’s interpretation of the rules governing model aircraft are overly broad, do not take into account technological advances made since the drafting of Congress’ working definition of ‘model aircraft,’ and the effects of a complete ban flying model aircraft for any type of compensation.

notgood

This is not a good comment.

Of course, if the proposed rules for model aircraft go through, the only option will be to turn to the courts. Historically, the FAA simply does not lose court cases. Recently, cases involving drones have come up with successful defenses and judges deciding in favor of drone operators. The legal services for the eventual court case challenging the proposed FAA rules will most likely be funded by the Academy of Model Aeronautics, who just so happen to be offering membership at 50% off.

Below is a video of some RC people we really respect – [Josh] from Flite Test and [Trappy] of Team BlackSheep – talking about what the proposed rule change would do to the hobby. There’s also a great podcast featuring the first lawyer to successfully defend drone use in federal court that’s worth a listen.

[Read more...]

THP Entry: The Everything RC Transmitter

OSRC With few exceptions, most of The Hackaday Prize are things we really haven’t seen much of before: base-3 computers that have been relegated to the history books, extremely odd 3D printers, and fancy, new IoT devices are the norm. The OSRC is not a new project to us. We saw it once in 2011 and again a year later. What makes the OSRC an interesting project for The Hackaday Prize isn’t the fact that it’s the most advanced RC transmitter ever created. Creating that was evidently the easy part. The OSRC could use a big financial kick in the pants, and if [Demetris] wins, we’d guess he wouldn’t be taking that ride to space. Rather, he’d be taking the cash prize to get his ultimate transmitter into large-scale manufacturing and out into the wild.

While at first glance the base model OSRC seems expensive at about $6-700 USD, consider this: a six-channel transmitter from an excellent brand costs about $120 USD. Nine channels will run you about $400. The OSRC is a forty channel radio. The sticks are capable of force feedback, and of course the ‘pro’ model of the OSRC has that wonderful screen, capable of displaying video from an FPV camera, a GPS/map overlay, or an incredibly extensive telemetry display. There are multi-thousand dollar avionics for real airplanes out there that have a smaller feature set, and that’s not hyperbole.

A few months ago, [Demetris] was interviewed by the awesome people at Flite Test. That (highly suggested) video is embedded below.


SpaceWrencherThe project featured in this post is an entry in The Hackaday Prize. Build something awesome and win a trip to space or hundreds of other prizes.

[Read more...]

Droning On: PID Controllers and Bullet Connectors

droning-on-hill Not all drones are multirotors – Posing in our title photo are Maynard Hill and Cyrus Abdollahi. Maynard’s plane, TAM5 aka The Spirit of Butts Farm, is the smallest aircraft to make a transatlantic flight (YouTube link). Retracing the path of Alcock and Brown from Newfoundland to Ireland, the 6 pound (dry weight) model made the trip in just under 39 hours. All this happened in 2003, and was the cap on a lifetime of achievements for Hill. These are the types of pursuits that will be banned in the USA if the FAA restrictions go into effect.

Flight Controllers

Quite a few of you thought the Naze32 was left out of last column’s flight controller roundup. I hear you loud and clear! I’ll add the Naze to the controllers which will be tested on The Hackaday Testbed. The hard part is finding the darn things! I currently have an Acro Naze32 on its way to Droning On HQ.  If I can find a full version, I’ll add that.

PID Controllers Deep Dive

I’ve gotten a few questions on Proportional Integral Derivative (PID) controllers, so it is worth diving in a bit deeper to explain what a PID controller is. PID controllers are often found in process controls managing parameters like temperature, humidity, or product flow rate. The algorithm was initially designed in the late 1800’s as a method of controlling the helm of large naval ships. In fixed wing drones, PID keeps the plane’s wings level and on course. In multicopters, PID loops control heading, but they also provide the stable flight which allows the quadcopter to fly in the first place. A full explanation of PID loops would be beyond the scope of a single article, but let’s try a 10,000 foot explanation.

pidP: This is the “Present” parameter. P Has the most influence on the behavior of the aircraft.  If the wind blows your quadcopter from level flight into a 30 degree right bank, P is the term which will immediately take action to level the quad out. If the P value is too high, The quadcopter will overshoot level flight and start banking the other way. In fact, way too high a P value can cause a quadcopter to shake as it oscillates or “hunts” for level. Too Low a P value? the quadcopter will be very slow to react, and may never quite reach level flight again.

I: This the “Past” parameter. The I term dampens the overshoot and oscillations of the P term, and avoids the tendency of P to settle above or below the set point. Just like with P, too high an I term can lead to oscillation.

D: This is the “Future” parameter, and has the smallest impact on the behavior of the aircraft. In fact, some flight controllers leave it out entirely.  If P and I are approaching a set point too quickly, overshoot is likely to occur. D slows things down before the overshoot happens.

So why do multicopter pilots dread PID tuning?  Quite simply, it’s a tedious process. Couple a new pilot and an unproven aircraft with un-tuned PID values, and you have a recipe for frustration – and broken propellers. Things get even more complex when you consider the fact that there are at least 3 sets of PID variables to be tuned – Pitch, Roll, and Yaw. Some flight controllers now support multiple PID values depending on the style of flight. Want your plane or multicopter to fly around like a hotrod? You need a totally different set of PID values than a docile trainer craft. Rolf Bakke (KapteinKUK himself) made a video illustrating how multicopters behave when tuning PID values. You can easily see how a quad can go from “drunk” to “angry bee” with just a few value tweaks. All this is coming together with The Hackaday Testbed, which will help me in posting a few PID tuning videos of my own.

Hackaday Testbed Update

As for the testbed itself, it’s nearly complete! You can follow the progress on my Hackaday Projects Page. Most of the assembly has been relatively straightforward.   though of course there are always a few snags. It seems I always forget something when ordering up parts for coils-bada build. In this case it was 2.5mm banana plugs and motor mounting screws.

The Hobbyking motors attach to the frame with 3mm screws. The problem is that there really is no way to know how long the screws should be until you have the motors, mounting plates and drone frame on hand. I have a bunch of 3mm screws of various lengths, and thankfully there were enough screws of the correct length to mount the motors. Murphy is always at my side, as I accidentally grabbed a screw that was 1mm too long and, you guessed it, screwed right into the windings of the motor. Doh! Thankfully I had spares.

bullet-solderBullet connectors can be a real pain to solder. There are some jigs out there which help, but I’ve always found myself going back to the old “helping hands” alligator clips. Bullets tend to use lower gauge wire than we’re used to with regular electronics. 14, 12, even 8 gauge wires are used on R/C aircraft. A low power soldering iron with a surface mount tip just won’t cut it. Those irons just doesn’t have the thermal mass to get the connectors up to soldering temperature. This is one of those places where a decent 40 watt or better Weller iron (yes, the kind that plugs right in the wall) can be a godsend. I’m using an Metcal iron here, with a wide flat tip.

bullet-solder-2Bare bullet connectors and alligator clips can also create a problem – the metal clips create even more thermal mass. Years back an old-timer showed me a trick to handle this. Slip a piece of silicone R/C plane fuel tubing on the bullet, and then clip the helping hands onto the tube. The tube will act as insulation between the bullet and the clip. Silicone can easily withstand the temperatures of soldering. I’ve also used the silicone tube on the jaws themselves – though eventually the jaws will cut the soft tubing.

That’s about it for this edition Droning on! Until next time, keep ‘em flying!

Title photo credit Cyrus Abdollahi.

Goliath: One Drone to Rule Them All

goliath

We see quadcopter projects all the time here on Hackaday, so it takes something special to get our attention. [Peter McCloud] has done just that with Goliath, a gas powered quadcopter he’s entered in The Hackaday Prize. By gas, we don’t mean a little glow fuel buzzer, We’re talking about a 30 horsepower V-twin lawnmower engine running good old-fashioned gasoline.

Multicopters powered by a single power source present a unique set of problems. Quadcopter propellers need to rotate in opposite directions to avoid the entire craft spinning due to torque action. With individual electric motors that’s as easy as swapping a couple of wires. Not so with a single rotating engine. [Peter] has accomplished this feat with a clever arrangement of single and double-sided belts.

Control is another issue. Generally, central powered multicopters use collective pitch, similar to a helicopter control system. [Peter] has decided to go with high-efficiency fixed pitch blades and a vane system for directional control. Much like hovercraft use vanes to steer, Goliath will use vanes to affect its attitude and yaw.

goliathPropThe propellers are works of art in their own right. [Peter] modeled the propellers in CAD using the principles of blade element theory, then used a Shopbot style CNC to carve them out of pink insulation foam. Styrofoam alone won’t withstand the 60 lbs each propeller will be supporting, so [Peter] plans to laminate the props in composite cloth. This is the similar to the way many full-scale helicopter rotor blades are assembled.

Goliath’s frame is constructed of Dexion style slotted steel angles, and we have to admit, at 240 lbs with engine, it seems like it’s going to be a heavy beast. Big enough to ride at least. Who knows… if the judges like it [Peter] may ride Goliath all the way to space!

 

 


SpaceWrencherThe project featured in this post is an entry in The Hackaday Prize. Build something awesome and win a trip to space or hundreds of other prizes.

Droning On: Choosing a Flight Controller

do4 The flight controller is the nerve center of a drone. Drone flight control systems are many and varied. From GPS enabled autopilot systems flown via two way telemetry links to basic stabilization systems using hobby grade radio control hardware, there is an open source project for you.

Modern drone flight controllers can trace their roots back to R/C helicopters. Historically, R/C planes were controlled directly by the pilot’s radio. Helicopters added a new wrinkle to the mix: tail rotors. Helicopters use their tail (or anti-torque) rotor to counteract the torque of the main rotor attempting to spin the entire helicopter’s body. It all works great when the helicopter is hovering, but what about when the pilot throttles up to fly out? As the pilot throttles up, the torque increases, which causes the entire helicopter to do a pirouette or two, until the torque levels out again. The effect has caused more than one beginner pilot to come nose to nose with their R/C heli.

The solution to this problem was gyroscopes, heavy brass spinning weights that tilted in response to the helicopter’s motion. A hall effect sensor would detect that tilt and command the tail rotor to counteract the helicopter’s rotation. As the years wore on, mechanical gyros were replaced by solid state MEMS gyros. Microcontrollers entered the picture and brought with them advanced processing techniques. Heading hold gyros were then introduced. Whereas older “rate only” gyros would drift, weathervane, and wiggle, heading hold gyros would lock down the helicopter’s nose until the pilot commanded a turn. These single axis flight controllers were quickly adopted by the R/C helicopter community.

Today’s flight control systems have many sensors available to them – GPS, barometric pressure sensors, airspeed sensors, the list goes on. The major contributors to the flight calculations are still the gyros, coupled with accelerometers. As the name implies, accelerometers measure acceleration – be it due to gravity, a high G turn, or stopping force. Accelerometers aren’t enough though – An accelerometer in free fall will measure 0 G’s. Turning forces will confuse a system trying to operate solely on accelerometer data. That’s where gyros come in. Gyros measure rate of rotation about an axis. Just as our helicopter example above covered yaw, gyros can be used to measure pitch and roll of an aircraft. A great comparison of gyros and accelerometers is presented in this video from InvenSense.

Stay with us after the break for a tour of available flight controllers and what each adds to the mix. [Read more...]

Chocolate Quadrotor Proves You Can Make Anything Fly

Chocolate Quadrotor

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.

[Read more...]

Analog Shield and PCB Quadcopter

 

We spent a little bit of time at the TI booth at Maker Faire to film a pair of interviews. The first is with [Bill Esposito] who is grinding away on his PhD. at Stanford. He’s showing off an Analog Shield for Arduino. He describes it as “an attempt to bring the analog bench to an Arduino shield”. We think this is a fantastic idea as most who are learning digital electronics through Arduino have little or no experience with analog circuitry. This is a nice gateway drug for the concepts.

The analog shield has a supply good for +/- 7.5 volts, 4-channel ADC, 4-channel DAC, and gets 100k samples at 16-bits. He showed us a spectrum analyzer using Fast Fourier Transform on the incoming signal from a microphone. He also built a function generator around the shield. And finally a synthesizer which plays MIDI files.

In the second half of the video we take a look at [Trey German's] work on a PCB-based quadcopter. His goal is to reduce the power consumption which will equate to longer flying times. To this end he chose the DRV8312 and a Piccolo to control each sensorless, brushless DC motor. The result should be 10% lower power consumption that his previous version.

 

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