RC aerial vehicles: because we don't have flying brooms

The Something Awful Forums > Discussion > Hobbies, Crafts, & Houses > RC aerial vehicles: because we don't have flying brooms

Snapshot: Oct 22, 2004; damnit Matt get in the boat

Crosposted from AI's Aeronautical Insanity thread:

I was looking at building a quad with friends, to get a stable camera platform/General Purpose lift platform also. The reason we didn't go with a tri-rotor is the control laws would be a touch more difficult. The camera we were thinking of was one of the new Elec. viewfinder/Interchangeable lens so it could be aimed with a through the lens view. The main problem is weight for us, We're looking to have 5kg of payload, including a flight cam and a high quality camera.

Ola, pressure gauges are easy, they're a 3 lead part, if I remember from the cansat. GPS stationkeeping may be a little more difficult, as gps can be imprecise, and slaving it into the controls would probably require kalman filtering. hover hold's been done. Check out the Parrot AR Drone. http://ardrone.parrot.com/parrot-ar-drone/usa/ Once you get a feed from the gyros, you have the control law hold the angles when it's hands off. That's also a very basic autopilot.

Edit: Definitely enough of a derail for a new thread.
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EDIT: Well, regarding the chute, you'd have a few issues: Weight, opening time, fouling in props, etc.

Snapshot fucked around with this message at 01:01 on Feb 4, 2011

# ¿ Feb 4, 2011 00:52

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# ¿ Apr 29, 2024 04:19

Snapshot: Oct 22, 2004; damnit Matt get in the boat

Ola posted:

What about a rather powerful TCAS transmitter and scare the poo poo out of airliners on final? But I guess that falls on the wrong end of that nitpicky "ethics" thing.

The information so far is excellent and Manny that is a very reasonable budget. Less than a GoPro camera!

One thing I'm wondering is if it's possible to stabilize the machine in hover hold with gyros. Is it? The idea would be to be able to fly it in relative mode instead of absolute mode. Don't know if that makes sense but:

Absolute: thrust lever controls thrust of engines, simple as that.
Relative: thrust lever becomes more like altitude selector. Hold up to go up, when centered the machine maintains altitude by itself.

You'd need some sort of accelerometer/barometer/altimiter. Gyros only give angular rate information. Once you have that, all that you need is a control law to neutralize z axis movement.

EDIT:

Nebakenezzer posted:

Was I just imagining things yesterday, or was the phrase "video goggles" used in conjunction with piloting these honkeys?

Yeah, you could use video goggles and a 2DoF head-tracking system to give yourself a decent view.

# ¿ Feb 4, 2011 19:10

Snapshot: Oct 22, 2004; damnit Matt get in the boat

Ola posted:

But a gyro should say when poo poo is moving and a controller should say "poo poo! poo poo is moving when I told poo poo to stay still." Airliners are perfectly capable (with some exceptions) of navigating across the world with only a gyro (albeit a very costly one) as their primary instrument.

I thought about this when writing the first post and my conclusion is this: It's not about flying a thing, it's about looking at something in a way you couldn't look at it before, with the added bonus of flying a thing. I.e. it's not about the craft filming the waterfall, it's about the waterfall, but the craft is really cool. And particularly when you can show it to other people in glorious HD.

The past two years of my SA account are mostly dedicated to motorcycling and that interest was triggered by people on the internet showing pictures and video and writing text about their motorcycling. Display and conveyance, holy poo poo they are good motors for storytelling.

(PS did you know there are enthusiast priced side scan sonar and ROVs? Yeah, I have no future which isn't already bought up by childish exploration at a prosumer pricepoint)

You're still getting some sort of linear input, via gps, or even by indicated air speed. Inertial Navigation Systems still have linear accelerometers in them. The problem with the gyros is that they sense angular data only - they don't sense movement, they sense rotation. If you move the craft such that it doesn't tip at all, as in a quad copter with contra-rotating props going straight up, you won't see any signal at all on the gyros. However without the gyros, you can't make sense of any of the linear data as you don't know the orientation of the craft wrt the ground.

# ¿ Feb 4, 2011 23:12

Snapshot: Oct 22, 2004; damnit Matt get in the boat

Ola posted:

Ok thanks, I'm getting closer to wrapping my head around this. As long as the gyros can keep it level you could set to engine idle speed to = hover and down throttle means sink and up throttle means climb. That could be done on the fly on the transmitter right?

Yeah, you could hold attitude using the gyros, although that would probably require some sort of onboard control system. You then would have to keep manipulating the throttle to get the hover that you wanted. You'd be providing the translation data with your eyes and the throttle input. You wouldn't be able to correct drift very well.

# ¿ Feb 7, 2011 20:53

Snapshot: Oct 22, 2004; damnit Matt get in the boat

evilmonkeh posted:

I've been designing my own radio + autopilot with accelerometer + gyroscope for the last few months, and the hardware is nearly ready to build. Hobbyking has a $15 Quadcopter frame which looks pretty good for testing so I've ordered one.

Radio + autopilot, eh? Details, Please! Are you licensed for a particular spectrum?

# ¿ Feb 9, 2011 15:44

Snapshot: Oct 22, 2004; damnit Matt get in the boat

evilmonkeh posted:

The whole system is based around a JN5148 2.4ghz zigbee microcontroller, has good range and is fairly fast. Using an IMU-3000 and ADXL345 as sensors. I'll post more details in the next month or so, going to order some PCBs soon then I can start proper development!

Ahh, low power unlicensed. I remember looking at those for the CanSat in 2007, or something similar. I'm looking forward to seeing this. For my quad that I'm designing, I'm probably going to take advantage of my amateur radio ticket, and up the transmitter power. That and probably use one of the GHz bands for the video feed.

# ¿ Feb 10, 2011 20:04

Snapshot: Oct 22, 2004; damnit Matt get in the boat

Manny posted:

https://www.youtube.com/watch?v=5wJUWzYuuqs

Thought this was quite neat.

Neat but pointless weight. The only time you're going to fold the copter up is on the ground. Also, I'd not want a fold wings switch easily accessible on the controller. If you hit that while flying, the result will be spectacular; I'd rather not tempt Murphy.

Manny posted:

https://www.youtube.com/watch?v=n55v_bZ5zTk

Yeah, that's a big old oops. On the upside, his camera's waterproof. I wonder how difficult it would be to install flotation bags on that thing.

# ¿ Feb 15, 2011 18:53

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# ¿ Apr 29, 2024 04:19

Snapshot: Oct 22, 2004; damnit Matt get in the boat

Schottingham posted:

Edit: Also some old HAM dude was telling me that RF can damage your eyes at a certain power level, even if it's not ionizing radiation. Is this guy loving crazy or should I actually be careful? I was under the impression that unless the radiation is ionizing, the only danger is from heat.

Yeah, however, the "sweet spot" for EM radiation absorption is near 400 MHz. You're well above it if you're working in the 2.4 GHz range. However, your duty cycle is much higher than the usual ham's. If you want a little more info, here's the US ham society's info on RF safety. I'll explain more later if you like, but my battery's toast.
EDIT: I forgot the bloody link: http://www.arrl.org/rf-radiation-and-electromagnetic-field-safety

Snapshot fucked around with this message at 20:08 on May 16, 2011

# ¿ May 16, 2011 20:05

The Something Awful Forums > Discussion > Hobbies, Crafts, & Houses > RC aerial vehicles: because we don't have flying brooms