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Ardu-IMU-Pilot Flys - First successful test flight made today!

Posted by Doug Weibel on December 15, 2009 at 3:30pm
Today the weather finally cooperated and I dashed off to my local flying field for a long lunch.

My Ardu-IMU-Pilot had two successful flights! Performance was quite poor, but considering that I changed all the control laws and picked gains out of the air I am satisfied that the UAV was able to complete the prescribed circuit (multiple times in fact).It is funny to see this track on google earth because in fact most of the ground today was covered in snow. I'll have to remember to see how snow cover affects the thermopiles some time.What I did:I converted my current UAV (Superstar EP airframe, Brushless/lipo power system, Thermopile based ArduPilot autopilot) to a IMU based system. To do this I used ArduIMU. I connect the GPS to ArduIMU and connect the serial output of ArduIMU to ArduPilot. I have modified V2.4 of the ArduPilot code significantly to use data from ArduIMU rather than the thermopiles. I have also modified the ArduIMU code to provide a binary data message to ArduPilot.Results:My test flights today proved out the architecture. The new autopilot system successfully provided stabilization and navigation. However, performance was quite poor and I need to do some tuning of both the code and the gains.I chose to completely change the control laws. I did this for two reasons. First, because this is open source and I can! Second, because I wanted to try out some ideas for the turn-rate limiter workgroup. Briefly, I added a cross track error component to the roll control loop (zero gain today), I changed the elevator control loop so that elevator is used to maintain constant airspeed, and the throttle control loop is used to maintain desired altitude.Trying out the new elevator and throttle control laws simultaneously with poor gain choices was a disaster. So, I quickly rewrote the elevator control to just hold zero pitch. With this change things went better.What went poorly:Well, my roll gains need adjusting. Rolling into a turn would produce bank angles in excess of the desired maximum, and there was a lot of wing wagging going on at times.Also, my quick patch to hold zero pitch I believe in fact was holding some amount of up pitch relative to the wing. When the UAV was below target altitude and the throttle setting was relatively high things went well. However when the UAV got above target altitude the throttle was reduced to a low level things did not go so well. The elevator continued to hold zero pitch, which was actually some amount of positive pitch, and the airframe slowed until it stalled. I found that it (my SuperStar) does not stall nicely, with a very pronounced tip stall. This produced a couple of unwanted circles during the mission.Going forward:I think my next step will be to do some manual flying with data logging to get some data on throttle settings versus pitch & airspeed. With that data I should be able to rework the elevator and throttle controls. I would also like to log some data during some manually flown aerobatics and see how my ArduIMU results compare with those being gathered by Jose Julio.
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3D Robotics

Other amateur UAV communities

Posted by Chris Anderson on December 15, 2009 at 8:30am
For those of you who just can't enough amateur UAV info, here are some other communities worth adding to your reading list: --RC Groups UAV forum: This is the grandfather of UAV discussion forums and the second biggest after DIY Drones. --RC Universe UAV forum: Not as active as RC Groups, but still worth checking out from time to time --AttoPilot User Group: Gary Mortimer's Ning site for AttoPilot users. If you've got one, this is a must --Paparazzi User Group: Ditto --CropCam/MicroPilot User Group: Ditto --RunRyder UAV Helicopter forum: I know nothing about helis, so perhaps someone could comment on this one? Weirdly, AUVSI, the industry association, doesn't appear to have any active forums. If you know of others, please highlight them in the comments and I'll add them here.
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Developer

Public beta of the Ardupilot 2.5 Airframe Test

Posted by Jason Short on December 15, 2009 at 12:00am
Hello everyone,The Ardupilot 2.5 Airframe Test is now available as Public Beta. It goes without saying that everything seems to work, but we could use your feedback finalizing this code.Use this release to:- Configure your 2.5 Header files- verify your sensors are functioning properly- verify your servos are not reversed- verify your stabilzation is pointing your plane AWAY from the ground- verify your failsafe is functional- output handy radio values for header files- view the throttle output based on your airspeed sensor- fly a fully stablized plane with throttle based failsafeThe failsafe will cause the plane to loiter slowly at the point of failure. Just try and grab the signal at the next pass. ;)The header file has been moved to be right inline with the other files for your convenience. There are a few hardware specific options listed at the top of the header. Set yours up to fit your plane. Note: If you use this without a Z sensor, you will need to calibrate the XY sensor. (Simply point each side of the sensor at the ground/sky before flying.)For debugging, all the output is sent to the Serial monitor at 10 Hz. You will seeRadio IN: R:1501 E:1500 T:1015 (rudder, elevator, and throttle)Analog IN 0:499, 1: 529, 3: 235 (X, Y, and Z from IR)Sensors: ir_max:305 roll:0 pitch:-4 airSp:0 (IR_max higher number = more resolution, roll/pitch are angles, airspeed should be 0 at rest)PWM OUT: R:1504 E:1517 T:1024 (rudder, elevator, and throttle)As well as:set_mode: ##5| AUTOPILOT The current flight mode indication based on control switch position.*** FAILSAFE DETECTED *** The throttle has dropped 50µs below it's normal cutoff. Set this in your radio's preferences.Radio calibration:When prompted, move the Rudder (ch1) and Elevator (ch2) to the extremes to set your maximum servo travel. You will be prompted to hold the stick into position to move ahead in the process. The servos will twitch, which can be a guide to calibration in the field.Throttle input is disabled by default. Solder a wire from your channel 3 input signal pin to pin 13 to read the throttle for failsafe. Set throttle input to 1 to enable it. (Highly recommended)Adjusting the gains for attitude control - There is really one gain to worry about and that is ROLL_GAIN, and PITCH_GAIN. Lower this gain if things are squirrely up there.This code will spin the propeller. Please be careful...Best of luck,JasonSee this post for the latest version.
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3D Robotics

MIT's Eric von Hippel on open innovation models

Posted by Chris Anderson on December 14, 2009 at 9:00pm

Famed MIT open innovation researcher Eric von Hippel has a new paper out on open innovation models, of which the DIY Drones dev teams are one. It's a pretty academic read, but I thought the framework he identifies in the above diagram was very interesting. I've drawn what I think the path of autopilots has been over the past five years ago, as the ease of communications between distributed participants and the falling cost of autopilot technology has taken what was once a military-industrial technology and made it accessible to open source teams such as our own. Did I get the arrow right?
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3D Robotics

Booz: New Paparazzi project for quadcopters

Posted by Chris Anderson on December 13, 2009 at 10:35pm
Over at RC Groups, there's an interesting thread about Booz, a new Quad Rotor UAV project that uses some of the Paparazzi code as its base. They write: "This thread will be a place for all things Booz including the progress of the Booz hardware myself and Gussy are getting made. This will be for sale shortly (around one week) and will sell for US$850 including cables. It has the following features: Complete hardware using the original Paparazzi BOM, no parts removed to save costs. LEA-5H GPS. Professional PCB assembly done by a local assembly house, not soldered at home using a electric frying pan or cheap eBay oven. All parts fully tested and with code loaded, as we are in Australia we can legally do this and export them worldwide. Cables included. We are also working on some 30 amp I2C ESCs, the hardware is complete and they will be MikroKopter compatible down to the software level. These will sell for just $35 each, however, will not be sold with software on them, just a boot loader which I still have to write."
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3D Robotics

DIY Drones live chat/podcast tonight at 9:00pm PST

Posted by Chris Anderson on December 13, 2009 at 9:00pm
Free video streaming by Ustream Tonight (Sunday) we'll do our tenth 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 at 9:00 PM PST and will probably go about 40 minutes. This week we'll by joined by Jason Short, talking about the next version of the ArduPilot code (2.5 and 3.0). As always you can subscribe to the podcast here. Tonight's livecast will be recorded and available as a podcast on Monday.
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learning to fly with ardupilot??

Posted by jim on December 13, 2009 at 6:54am
Does anyone know if it's possible to use the ardupilot as a training aid.I'm about halfay through building a model trainer that looks like a microlight from the book 'Learn to make models that fly' called the 'Micro-T'. I intend to use this model to teach myself how to fly as my nearest modelling club is more than 50 miles away. (There is one thats closer but say they don't have a qualified instructor)Anyway could I build his model and have the ardupilot control certain functions till I get up to speed?Some off hand stats are:Span; 60"Power; .28cuin pusher4chThe best bit is that its a pusher and the last chapter on this model shows a conversion for a photo module. Easy enough to turn it into a UAV after I learn to fly (Hopefully).Thankyou for any replies
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ArduPilot AND BlimpDuino featured on Make

Posted by Pokoleo on December 13, 2009 at 12:56am
I noticed this story on one of my newsfeeds. Looking into it, it looks like BOTH Ardupilot and Blimpduino were listed as "Make Online Open Source Hardware 2009" projects. Most notably, ArduPilot was listed first in the UAV subsection, with the BlimpDuino being listed second.UAV SPecific page: here, main page here...noticed that they describe the ardupilot as the blimpduino though...If anyone's posed this so far, feel free to remove this post.
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3D Robotics

New product in the DIY Drones store: 8-ch PPM encoder

Posted by Chris Anderson on December 11, 2009 at 10:52pm
The best way to read RC signals is PPM, which is a sequential stream where each channel is output in turn on a single wire. But traditionally the only way you can get that is to open up your RC receiver and solder a wire to a special pin. Fortunately the Paparazzi team designed a board that will convert up to 8 channels of regular PWM servo signals to one PPM signal, with no RC hacking required. We've now modified it a bit to work with our failsfe multiplexer and released a version as a DIY Drones product ($24.95). BTW, the forthcoming ArduPilot Mega will use this technique, as well. From the product description:"This improved & reduced PPM encoder board, based on a Paparazzi design, plugs into the servo output ports on a R/C receiver and encodes them into a PPM pulse suitable for the paparazzi autopilot and other projects. This allows you to use any R/C equipment with the paparazzi autopilot or read up to 8 servos with a single I/O pin of your uController. Modifications to the R/C receiver are not necessary. Connect the wires from your receivers channels to the PPM and one wire to the PPM in of your system. If you decide to use the tiny board to power the receiver, make sure you put-in a jumper and plug something between the 8th channel and the receiver. The whole project is based around the ATMEL ATMEGA168/328 AVR processor and all timing is done within interrupts so accuracy and stability is optimized It is now also possible to select the PPM waveform shift, negative or positive. Firmware is free and was created by Hendrix and Moa, with tiny modifications by Jordi Muñoz that allows control an extra failsafe multiplexer.
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Using ArduPilot as an aerial minesweeper?

Posted by Tom Yochum on December 11, 2009 at 2:03pm
I read in Aviation Week (Nov 16th issue) about the International Astronautical Federation and the Minseeker Foundation teaming up to study landmine detection from space. Landmines are a terrible leftover from war in many developing countries. There are an estimated 100 million landmines in the world, and they kill or maim 15,000 to 20,000 people each year. Many international organizations are working on ways to efficiently remove these landmines.This got me thinking about the feasability of using an inexpensive UAV as a minesweeping platform.The biggest hurdle, or course, is developing a payload that could detect landmines from the air. I figure if someone thinks they could do this from low earth orbit, they could make a smaller package that could do it from 100 feet. Does anyone know of anyone doing research into this sort of thing? Anyone have a grad student friend looking for a research project? I am sure there is research money out there to fund this sort of project.What would be required from an aircraft perspective? Again the payload size and weight would ultimately dictate the airframe, propulsion, and other parameters. But what about the avionics? Could ArduPilot provide the navigation, sensor orientation and geolocation information with sufficient accuracy? Could it maintain a desired altitude above ground (using a laser or sonar altitude sensor)?Is this just a science-fiction fantasy?Tom
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THIS WEEK IN AEROSPACE

Posted by Jack Crossfire on December 11, 2009 at 10:30am

There it is. The coveted $3.30 14.7456Mhz crystal. With that & a small bugfix installed, the C328 works perfectly at 115200, the pictures stream continuously from the microcontroller & we're up to XBee lockups.Even 1 way communication locks up in this high interference environment because the ACKs collide. Your only option is broadcast mode. With broadcast mode & 3 retries, you now have more errors but the Xbees don't lock up. The command to set the number of retries is ATRR & it's undocumented on the XBee 900.With the 900Mhz & 2.4Ghz running simultaneously we now see the huge difference in range. The 900Mhz dies at 300ft, much closer than the 2.4Ghz. This is with wire antennas. Since 900Mhz has always been more expensive than 2.4Ghz, don't expect to get 2.4Ghz range out of 900Mhz for $42. High gain antennas are required. Dual 2.4Ghz modules don't work well either.So that's $140 for 300ft .2fps 320x240 video. Ended up with this arrangement because 900Mhz was originally supposed to be for telemetry. The C328 was a cheap way to get preview video by recycling the 2.4Ghz radio. It's clearly a disaster compared to what people are doing with a $90 Ativa/Camileo & $80 Range Video radio.http://rcexplorer.se/page14/hdcv/hdcv.htmlvideo.tar.bz2This is the updated source code for the wireless camera system.This is our full motion aerial footage of the Rain Ramon XMas tree. The autopilot was programmed to always point towards the tree, but L1 GPS & GPS derived heading being what it is there was a lot of manual intervention. If the weather wasn't already closed in for the year, we would fly this at 1m/s with manual heading & time lapse it to get more accuracy.Heading from the magnetometers & accelerometers back in the day was never very accurate either. Dynamic acceleration & local induction always made it approximate.& this is a segment from a very old flight showing a fast autonomous descent into downwash using the Marcy Maneuver.MARCY 1 VIDEO NOTESMain ideas for getting video out of Marcy 1 revolve around using 1 raster line of a chip camera like the TCM8230MD, but no data radio has enough bandwidth to do the job. So the best idea is to scan 1 raster line every several revolutions, stick with a photodiode for heading & use the rotation period to figure out where the rasterline was scanned. Accumulate rasterlines from many revolutions to construct an image.The camera would be read on a 2nd CPU. Data would be sent to the main CPU's UART & multiplexed on the main radio.MARCY 1 MISERY

So gEDA had the wrong footprint for an SSOP20 & we had to make a new ground station board. Fortunately it only requires remaking 1 side when your double sided boards are stacks of 1/32" boards.The PIC18F14K50 has USB & programming on the same pins, so in circuit programming is extremely slow without a bootloader & USB probably doesn't work with the programming header attached. You're looking at pogo pins & a jig.Since USB hasn't worked between this week's commutes, probably going to make the ground station radio a breakout board & use a chip with dedicated USB pins as the ground station CPU.

Flight computer ready.

MEET MARCY 2

While waiting for Marcy 1 parts to arrive from Thailand, started the Marcy 2 vehicle. She's planned as a backup indoor sonar demonstrator in case Marcy 1 doesn't work. The parts are all in apartment. Probably going to use the programming pins for PWM.She uses a no brainer 3 gyro, 4 PWM, 1 sonar autopilot. Could have just recycled Vika 2's autopilot but all our indoor vehicles need 900Mhz radio & sonar on the main board. Though capable of flying a tri rotor, Marcy 2 is planned as a tail sitter.The main problem is fabricating a tail sitter small enough to fit in a $1 million apartment.
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MatrixPilot 2.0 Released for UAV Dev Board

Posted by Ben Levitt on December 11, 2009 at 12:40am
What's New in MatrixPilot 2.0
  • Combines the functionality of MatrixNav and AileronAssist into a single firmware.
  • Supports navigation using both ailerons and rudder.
  • Increases the number of Radio Input channels (from 4 to 5), and Servo Output channels (from 3 to 6).
  • Supports controlling Delta wing and V-Tail airframes, in addition to Standard airframes with or without ailerons.
  • More responsive to switching between Manual, Stabilized, and Waypoint modes.
  • Supports using the new uBlox GPS for faster navigation responses.
  • Super-basic camera stabilization code.
  • Adds serial telemetry output in a variety of formats.
    • Supports telemetry output in our own UAV Dev Board format.
    • Supports telemetry output using an Ardupilot Ground Station compatible format.
    • Supports NMEA output to a Remzibi OSD.
During my reorganization of Bill's excellent code base, I've been focusing on making it more configurable, more maintainable, and more easily extendable. So hopefully progress on this project will continue to accelerate! We have a growing group contributing code and testing through our email list, and we suggest that you join the list if you are an active user of a UAV Dev Board!More info including downloads, a budding wiki, and our searchable subversion repository are available on our google code project page.And of course, giant thanks to Bill Premerlani for the awesome hardware, for providing such a strong software foundation, and for tirelessly answering all of my questions.
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Camera setup for my future UAV

Posted by Jason on December 9, 2009 at 2:30pm
My UAV build has officially started. In order to make the whole process easier, I am taking one system at a time. First up is the camera setup. Not necessarily a logical starting point but I have the camera and I can always use it on an RC aircraft until the UAV is done. Also, this gives me a chance to practice with it and tweak.I used a Webbie for the camera. Just remove three screws and carefully pop the back cover off to gain access to the photo and video buttons.

You can see the four wires on the left side of the Webbie (bottom of pic) for the focus and shutter control of still pics. On the right side of the Webbie (top of pic) are two wires for the video control. The "goop" you see is hot glue. I added it to keep things in place and allow the Webbie to function normally if necessary. The hot glue detracts from the surgical soldering job I had to perform in order to add the wires to the small surface mount components. Very tight in there.

I bought the switches I used to control the camera here.

Here I have the camera temporarily mounted to my EZ-400G for testing. I thought testing as many systems as possible on a reliable aircraft was a good idea. This aircraft also happens to have an FMA Copilot on it. It is a very stable platform.

Here is a pic from the first flight test.

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3D Robotics

Summer robotics intern positions at PARC

Posted by Chris Anderson on December 8, 2009 at 10:44am
These are dream internships, at Xerox PARC in Silicon Valley: Autonomous robotics - summer The intern will develop autonomous capabilities for mobile robotic platforms such as unmanned ground vehicles (UGVs) and unmanned aerial vehicles (UAVs). The focus of this effort is on probabilistic algorithms for sensor processing, motion planning, and vehicle control. The overall goal is to develop increasingly integrated model-based motion planning software that uses sensor models, agent models, and models of the physical surroundings, enabling interaction with unknown environments. Responsibilities include: deriving new algorithmic approaches consistent with the applicant’s background; developing them in simulation; and potentially applying them to existing UGV or UAV testbeds as appropriate. Requirements: Graduate student candidates in engineering and computer science Strong skills with C/C++ or Matlab for system simulation and implementation Background in optimization, statistics, artificial intelligence, and control Practical experience in robotics Robotic localization, mapping, and planning - summer The goal of the DARPA-funded LANdroids project is to deploy a team of robotic sensor nodes in an unknown environment to sense and report events to a tactical control center. Our project goal is to create efficient representation for both physical and radio environments, including mapping and localizing a team of robots using radio and short-range sensors. In addition, we are interested in algorithms for cooperative motion planning for physical search and exploration in unknown environments. Requirements: U.S. citizenship or permanent residency is required for this position Strong theoretical background in optimization and probabilistic reasoning -- with practical experience in robotics and good programming skills in both Matlab and C/C++ Graduate students in a relevant field (electrical engineering, computer science, or similar) are preferred, but we will also entertain applications from exceptionally strong undergraduate students with relevant experience [thanks to sonal chokshi for the tip]
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Pretty cheap camera+DVR system

Posted by Ty on December 8, 2009 at 9:54am
http://www.supercircuits.com/Security-Cameras/Specialty-Security-Cameras/RCCAM1?cmpid=136Sorry about the commercial post. Not my company, not affiliated with them in any way.

633857740442265000_RCCAM1-LEFT.jpg

The specs: 3 inches long, by .75 inches wide, weighing in at less than .75 ounces.I'm super-poor, or I'd be trying to pick one of these up (eventually to modify for pan and tilt). If anyone does pick one up, I'd be interested in hearing how stiff the camera head is.
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