It’s A Bird, It’s A Plane, No It’s a UAV I thought we should look into some interesting stories about the history of UAVs (Unmanned Aerial Vehicles) before we get into the sizzling high-tech advanced hunter-killer UAVs later in this series. We started the series last week with Robot Planes Win With Northwest Nano an intro to Northwest UAV, a local designer and builder of UAVs. This week we assembled some lighthearted stories, photos and videos covering a little history of UAVs, Hollywood and other fascinating flights of fancy for Friday Follies. So please come with me as we join Mr. Peabody (a smart talking dog long before snarky Brian) and his boy Sherman in the WABAC machine to travel to England in the early 1930s to meet Reginald Denny.
Reginald Denny 1917 Reginald Denny and the RadioplaneThe first large-scale production, purpose-built drone was the product of Reginald Denny. He served with the British Royal Flying Corps during World War I, and after the war emigrated to the United States to seek his fortunes in Hollywood as an actor. Denny had made a name for himself as an actor, and between acting jobs, he pursued his interest in radio control model aircraft in the 1930s. He and his business partners formed “Reginald Denny Industries” and opened a model plane shop in 1934 on Hollywood Boulevardknown as “Reginald Denny Hobby Shops.” Wikipedia |
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| Project | Team leaders |
|---|---|
| ArduPilot hardware (classic & Mega) | Jordi Munoz and Nathan Seidle |
| ArduPilot software (classic & Mega) | Jason Short and Doug Weibel |
| ArduIMU hardware | Jordi Munoz |
| ArduIMU software | Jose Julio, Doug Weibel and Jordi Munoz |
| ArduPilot Mega IMU shield | Jordi Munoz and Jose Julio |
| Ground station software | Igor Koruga |
| Configuration utility | HappyKillmore |
| ArduStation Mega | Sarel Wagner |
| Telemetry data structure | Mikko Saarisalo |
| Documentation | Chris Anderson |
Each of those team leaders typically has a few other contributors working with them; in total we probably have about two dozen core developers. These project are all sized to work best with small teams, so we're careful about adding too many new folks, but we also depend on the community to drive the project forward. So if you would like to contribute to one of these efforts, please comment below.
The answer is:
since UAVs are supposed to fly gracefully,
if you pick a platform that is manageable in manual mode (not overly sluggish),
you can fly a machine of arbitrary size.
Also the stall recovery using rudder is intuitive.
IMO positive stability is not strictly required,
but for real-world applications aircraft stability and autopilot action should better be working together.
MultiplexFox (0.26kg, no payload, 20-45min enduirance, 45-55km/h)
Research plane - classified as Barely Flying Machine. -40deg glide slope when unpowered.
Autopilot is the supporting structure... (maybe World's first Intergral Autopilot Design ;-) )
EasyUAV (1.2kg AUW, 0.65kg empty weight, 20min-1h10 endurance, 35-45km/h)
Pteryx UAV (3.2-5kg AUW, 2.6kg empty weight, 20min-1h30 endurance, 40-55km/h)
Fully custom UAV for aerial photography, not available as a kit or in any other form.
(a joint development of AerialRobotics and TriggerComposites, www.pteryx.eu)
All can be hand-launched, however for Pteryx with over 4kg AUW
it is possible to use bungee launch if you want to operate reliably
even under stress.
Tonight (Sunday) we'll do our regular podcast, which everyone here is welcome to participate in by listening to the chat live above and commenting and asking questions via the DIY Drones chat function. We'll be starting 9:00 PM PST.
This week we'll by joined by Krzysztof ("Chris") Bosak, creator of Flexipilot, a custom IMU-based autopilot, and EasyUAV. He'll be calling in from Poland, so I'm guessing this involves an early wakeup. Thanks Chris!
Here's a little background on EasyUAV. One of the questions we'll be asking him is when a proper website is coming ;-)
Today the $170 Raven clone we were talking about the other day arrived. Here are some quick impressions after unpacking it.
First, it's BIG. The wingspan is 60" (152 cm), which is about 15% bigger than the real Raven RQ-11 (130cm). Here you can see it head to head with a stock EasyStar.
The build quality seems pretty good. It's all balsa/ply, with no fiberglass or plastic. The tail boom is an aluminum tube. None of it seems very sturdy, however--this is nothing like the real Raven, which is made of carbon fiber and kevlar and designed to crash land.
However, the model comes with NO instructions, and I really have no idea how the wing is supposed to attach to the body, or where the CG is supposed to be, to say nothing of where the rudder and elevator servos are supposed to go, since the interior of the body is totally empty. There are hatches in the wing for the aileron servos, but no mounting rails.
The tail boom just slides into a hole in the body. I guess you're supposed to drill screw holes or something. No clues given.
The motor mount. No information given on suggested motor or prop.
Here's the inside of the body. Basically, this is an empty vessel. You'll have to do a lot of work creating a plywood interior framework for electronics and such.
It comes with a small bag of generic hardware, including some joke foam wheels and mounting brackets for landing gear that it doesn't have. This is almost certainly a hardware pack intended for another plane. There seems to be no connection to the Raven, although the control horns and fabric hinges could certainly be used on this model. Perplexing...
Bottom line: I really don't think this is the plane for me. Even with instructions, this is going to take many hours to get ready to fly. It's going to be hard to transport, with its large size and one-piece wing, and I'm worried about how it will handle hard landings. The tail boom mount looks fragile to me, and I really can't see how the wing mount can be anything but a fracture waiting to happen.
I think this might work as a very large display model for shows, but I can't really see it holding up to much real flying.
And without instructions, I wouldn't even try making it. For a $170 model, I'd expect more polish. In short, based on what I've seen so far, I can't recommend this.
I ran across this if anyone is having trouble grasping the concept of PID loops. Great, simple explanation:
http://www.pc-control.co.uk/feedback_control.htm
Rim
Gary Mortimer and I are leaning towards a simulation round for the next T3 contest, but I need some feedback about what would work best.
There are two kinds of simulations: "open loop" and "closed loop".
Open loop means that you connect the output of the simulator to the input of the autopilot. The simulation drives the autopilot with synthetic GPS coordinates and sometimes synthetic attitude data, essentially replacing the autopilot's sensors. This basically fools the autopilot into thinking that it is flying, and you can watch how it responds. This is typically done by having the simulator output data via the serial port and feed that into the autopilot.
Closed loop means that you also connect the output of the autopilot to the input of the simulator, so that the autopilot is "flying" the aircraft on screen. This usually requires a relatively complicated bit of hardware that converts the PWM servo output of the autopilot into what amount to joystick commands via USB or serial that steer the plane in the simulator. It can also be done entirely in software on the host PC, as in the case of Matlab simulations being driven by a flight simulator.
Here are some blog posts that show examples:
--Curt Olson's FlightGear demo
--Faisal Shah closes the loop, Part 1
--Faisal Shah closes the loop, Part 2
Here's a proposed contest structure:
Two sets of winners:
Both must write "DIY" (in cursive) over a place of their choosing.
--Group One: Open loop (video showing you mirroring the airplanes control surfaces with the arrow keys): First six to complete this win a $25 gift certificate to the DIY Drones store.
--Group Two: Closed loop (aircraft controls the flight simulator): First three to complete this win a $50 gift certificate.
What do you think? Is this doable?
AIRFRAME OPTIMIZATION HELL
Mainly, going from something that flies to something worthless hoping to someday get something more efficient flying again. The fact is Marcy 1 didn't have enough lift to do what She needed to do.
Got a wing from a discontinued glider to try to improve Marcy 1's efficiency.
It looks horrible compared to the beveled sheet & it's heavier. Everything needs to grow to balance it. You need a bigger balance beam to counteract its moment of inertia. It has to be bolted. It has unnecessary winglets since we have full cyclic control. It takes full power to get off the ground & quickly falls back down.
Went back to a glued balsa sheet but an enlarged balance beam. The best monocopter is completely glued even if every broken propeller & crash is a rebuild.
That got no meaningful improvement. The larger balance beam didn't improve attitude stability either. It's not loss of lift but loss of reserve power for translation. We as hover experts don't think she has enough attitude control to hover using sonar.
Also got rid of the inductor & relied on software instead. It's actually bearable with all the filtering required for attitude sensing.
The next step is a steeper angle of attack. Angle of attack changes require rebuilding the entire Marcy 1 but it's no worse than what goes into mocking up a human rated aircraft.
The steeper angle of attack was a disaster.
Despite your intentions of achieving fixed wing efficiency out of a rotary wing, a monocopter still gets most of its lift from just the outer part of the wing. People usually make it fatter on the outside or hang it on a long boom. Next comes longer wings.
That did slightly better in the wind, climbing even with full cyclic, but we're out of calm weather until next month. Going longer means no indoor use, so next comes going wider. A wide 1/16" sheet might actually work.
Undoubtedly going to require a longer balance beam to overcome pitch. This actually seemed to work well, but there's no such thing as a calm day in Calif* in April. Can get maybe 20 seconds before she's blown down the golf course.
THE WAR ON ALUMINUM
Next, the war on aluminum nuts continues.
Any threadlock completely destroys the prop. Down to plumbing tape & just letting it strip.
Overall, the Marcy 1 program sux.
MARCY 2 IDEAS
Been thinking of a long duration hover vehicle using 2 large monocopters bolted to a fuselage or a larger monocopter for outdoor use, but some people still get excited about tri rotors. Don't feel another tri rotor is advanced enough to call a Marcy vehicle.
Long duration hover requires a larger lifting area than any propeller or helicopter rotor can give. Pitch would involve differential thrust. Roll would involve throttle modulation from Marcy 1. Yaw would involve differential roll. Bearings would come from the Corona parts.
This would give 6 degrees of freedom from only 2 PWM's. Marcy 1 gets 3 degrees of freedom from 1 PWM.
It would need 3 batteries & 3 full duplex radio links to the ground. 2 would control the monocopters which would use beam cutoff sensors instead of magnetometers & no thermopiles. An IMU on the fuselage would detect attitude. They wouldn't need balance beams.
1st step is flying a big monocopter with a larger battery, motor & a dummy balance beam. That would prove longer flights were possible.
It's hard to justify the amount of work going into thermopiles if no future vehicle is going to use them. With the payload limitation & open space requirement, Marcy 1 is never going to do more than POV lighting at night. Monocopters can't bank enough to counteract wind because their magnetometers lock up.
When the weight of the monocopter is factored in, she doesn't get much more thrust out of the motor than a bare propeller. A bare propeller + flap would probably do better but couldn't do POV.
So it's heading back to the original plan of Marcy 2 as an indoor tri rotor & Marcy 3 as a VTOL Predator. Marcy 1 would be a toy for POV, maybe autonomous but more likely manual.
I came across ScanEagle video on EngineeringTV that showed ffew things that I din't know about it - each wing is attached to fuselage by one pin, motor mount is very flexible ( for vibration isolation) - there is a good shot of it towards the end of the video. Video has two parts and there is comerciall in the middle ( i.e. don't close the video when commerical starts ( ~ 2 min into the video...)
http://engineeringtv.com/blogs/etv/archive/2010/03/25/scaneagle-unmanned-system.aspx
http://www.popsci.com/technology/gallery/2010-02/gallery-future-drones
I found the inverted v-tails on some of them interesting, can anyone enlighten me on the advantages they present compared to normal v-tails or even more conventional tailplanes? I've seen one or two blog posts with similar mods, but it seems all it does is save weight.
http://uavkes.blogspot.com <- our blog
Hi, this is my first post in these forums. I'm an avionics software developer working on a CS Master's with no robotics background (beyond some Lego Logo and Mindstorms stuff way back when) but I'm looking to change that for my Thesis.
I'm looking at researching and developing a simulation environment for use in drone fleets (primarily UAV but I want it to be useful for ground and sea drones as well). While I want a reasonable basic physics handling of each unit my primary focus is going to be communications between multiple units of a BVR fleet.
Any suggestions on what I might want to consider or any research material I might find useful would be terriffic!
The competition held on March 20 and 21 in Taiwan. There are various events in the competition. Please refer to the official site : http://www.iaa.ncku.edu.tw/~whlai/uav/2010/
One of the events is Beyond-Vision-Range Flight. The airplane should fly far away and take some pictures of ground targets. The locations of tragets in the competition are shown in the following figure. The farest waypoint is about 3 km from home location.
We used EasyStar as the vehicle and UAV devBoard as the contorller. The plane crashed twice due to EMI problem before the successful flight. Because of the strong wind, it deviated from the expected flight path and disappered in the sky for about half an hour. When we were going to give up and the referee had asked the next team to take off, it suddently showed up above the home location. The crowd cheered as the plane safely landed on the runway.
Soon this platform will be ready and it's made for FPV / UAV flying for the amature marked.
Made of glassfiber.
Wingspan: 1,6 M
.
I will update this page as soon I have more info..
http://www.insidegnss.com/node/1918
Hi all,
This is the weekly report of ardupilot mega development :-)
We have developed the library for the DataFlash log memory. This function is really interesting, because we
would record the flights without the need to carry the laptop and telemetry all times... For example, for
testing the code I simply connected an small battery to the ArduPilot Mega, go outside to make the tests
without need of laptop, cables,... and then I download the results on laptop to analyze it. I´d like it.
Finally we use the standard SPI for the DataFlash chip and we change the AP_ADC library to use the serial port 2 in SPI mode. This way we sepparate the ADC (that is running inside an interrupt) from the standard SPI, and users can use also the SPI for other external devices. Also the ADC code can run a bit more efficient (now all ADC stuff at 400Hz use 3.7% CPU).
The DataFlash library isolate the user of the complexities of the internal registers, double buffer and page
distribution of the AT45DB161D flash memory. The library provides the functions to make sequential write and
read sessions and it´s written to be very efficient in the write sessions (it takes about 28us to write a byte,
this is near ten times better than a stardard serial port at 38400).
We have also converted the GPS code (Ublox) to a standard library. We will implement in the future libraries for other GPS (NMEA, EM406, ...). If all the libraries share the same interface, to change the GPS you only need to include your GPS library. Also this libraries are usefull for other DIY projects and Arduino users... (We made the library compatible with Atmega1280 (on serial port1) and also Atmega168/328). I could work on the library for NMEA GPS´s (I already have an Locosys) but I don´t have EM406, so somebody could work on this...
Now we have all the core parts of the future Ardupilot Mega running succesfully.
I´d really like the aspect of the code with the new libraries... It seems more easy, and an easy code is easy to maintain and modify by users...
The test code uses this:
- APM_RC : library to read the radio and output to servos
- APM_ADC : library to read data from the analog sensors (accels, gyros, ...)
- DataFlash : library to write/read to the flash memory to record flight parameters (log)
- GPS_UBLOX : library to access to the Ublox GPS
- IMU DCM code
Here are the codes:
Main test code: APM_Core_Test2.zip
Note that this codes are betas and will change when Jordi release the final version of the sensor shield because there will be different pin assignments.
One more thing I´d like to comment is that the new Ardupilot Mega main boards comes with a 16Mhz crystal for
the PPM encoder and works very great!! Now, the noise on the radio input is below 1us, this is nearly perfect Jordi...
Jose.
[There was a bunch of very cool Tri/Quadcopter stuff on the RCG blogs today. Here's a sampling:]
Above: A very cool custom tricopter with a Trex body so you can tell which direction is forward. Check out the post for details on the pro quality pan-tilt camera mount.
And check this next one out. Did you know that you can make a Mikrocopter amphibious? This video is mindblowing. It starts underwater, but keep watching:
Finally, a "best of" video of Mikrocopters as camera platforms. How many Hollywood movies or TV shows have you seen recently that used quads rather than cranes?
Both of those quad videos are from this post, which is great introduction to Mikrocopters. Worth reading the whole thing.
Sparkfun created their own 3D model of their HQ for the Autonomous Vehicle Competition, which they've submitted to Google Earth. It's good, but I like our own Graham Dyer's version better (bellow). His has the Evil Trees!
First I wanna congratulate all of you with all the things you've achieved already!
Now I have question:
I have to do a large school project, I have almost a year to complete it, and I want to make an IMU and display the data graphically using a rotating cube. I've done a lot of reading on this site already, and this is what i came up with:
My idea is to use the UAV Dev Board as a starting point. I would make my own board based on the UAVDevBoard, and rewrite the code (Yes I know I'd be reinventing the wheel, but thats part of the assignment :P).
Because the IMU would not be moving a lot, I won't be able to use GPS data for yaw correction (Right?), so I would need to use a magnetometer (Right?). And if so, what kind of magnetometer would I have to use? I was thinking a 3-axis tilt-compensated magnetometer like this one: http://www.sparkfun.com/commerce/product_info.php?products_id=8656
Also the sparkfun description of the UAVDevBoard kind of confuses me, because it says
"dsPIC runs at 120MHz with 16MHz resonator and PLL"
Now I understand that PLL can multiply the clock speed. But my understanding is that it can only multiply by 4, 8 or 16, none of which give 120MHz. Also the datasheet says that PLL can only be used with a 4-10MHz oscillator.
And finally, in the code i can't seem to find the place where the PLL is set?
Could someone maybe explain to me how they got to 120 MHz?
With regards,
Wouter van Verre
1 horsepower = 7 pounds
I've come across this magic number using different sized rotors, props, and engines in large RC helicopters and planes, and also researching horsepower to lift divided by time in several ultralight and light sport aircraft and rotorcraft, and this is a good rule of thumb when developing something that needs to do more than hover or drift in the wind.
Guidelines for precise calculation of lift or thrust
http://www.heli-chair.com/aerodynamics_101.html
Comparison information using UAV specialist developer information
http://www.barnardmicrosystems.com/L3_engines.htm
Be sure to click on the different links for engine type (4 stroke, wankel, turbine, etc.) In fact, Barnard Microsystems is an excellent reference for those looking to DIY a larger drone, and is highly informative reading material in all aspects of UAVs.
