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3D Robotics

Turning optocouplers into servo amplifiers

Posted by Chris Anderson on January 29, 2010 at 11:30pm

If you're using the UAV DevBoard with Futaba equipment or any other modern RC gear that outputs servo voltage of less than 3v, you're going to need a servo amplifier (also known as a booster or buffer) so the autopilot can reliably read your signals. You can buy one from a commercial supplier like FMA for $15, or you can use our dual optocoupler and save yourself $10 for each pair of servos you amplify. Out of the box, our optocouplers are designed just to clean up the RC signal, which is handy if you've got RF noise messing with your RC system. But if you solder two rails on the board (shown below), they become a very effective two-channel servo amplifier.

Make sure that the "input" side goes to the RC receiver and the "output" side goes to the servos or UAV DevBoard, like this (servo option shown):

When you're done, the servo amplifiers will take any input voltage and output a healthy 4.8v. Here's my scope data, from a Futaba FASST 2.4 Ghz system. Before amplification:

After amplification:

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Moderator

Septentrio to Release the AsteRx3 Compact GPS/GLONASS/Galileo Receiver

Posted by Gary Mortimer on January 29, 2010 at 10:00pm
What GPS lock problem..... AsteRx3-OEM-W.pngSeptentrio will start shipping its new AsteRx3 receiver in the first quarter of 2010. The AsteRx3 is, a compact multi-frequency GPS/GLONASS/Galileo, and Compass-ready receiver designed for integration in demanding precision positioning, navigation, and automation applications such as land and maritime survey, machine control, UAV payloads, and others.Providing simultaneous access to legacy and modernized GPS, GLONASS, and Galileo signals on L1, L2, L5, E5a, E5b, and E5 AltBOC, AsteRx3 is a compact and future-proof original equipment manufacture (OEM) receiver on the market, the company said. The receiver has a range of features, collectively known as GNSS+ . ATrack+, Septentrio’s patented Galileo AltBOC tracking, provides low noise tracking and multipath resistance for Galileo’s most advanced signal. LOCK+ tracking guarantees tracking stability under high vibration conditions.The advanced multipath mitigation algorithm APME has been extended for use with the modernized signals, and provides multipath mitigation especially for the predominant and harmful short-delay multipath. AIM+, Septentrio’s Advanced Interference Mitigation technology, protects receivers against in-band interference, and allows users to identify the interference in a “spectrum plot” view. These innovative tracking algorithms are complemented with RTK+ for extended RTK baselines over 50 kilometers as well as faster initialization.“With the evolution of GNSS systems, more and more users demand the possibility to prepare for the benefits these new signals and systems bring,” said Peter Grognard, managing director of Septentrio. “AsteRx3 exploits the capabilities of these signals with our latest ASIC technology. As AsteRx3 is one hundred percent plug-compatible with AsteRx2 and AsteRx2e, the AsteRx family is ideal for system integrators to build solutions which perform optimally with signals available today, which can be migrated to new signals and systems seamlessly tomorrow.”http://www.gpsworld.com/professional-oem/news/septentrio-release-asterx3-compact-gpsglonassgalileo-receiver-9467
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3D Robotics

"Living With Robots", an excellent 8 min documentary from Honda

Posted by Chris Anderson on January 29, 2010 at 1:58pm
From BotJunkie: "Honda was also at Sundance to screen a wonderful 8 minute documentary called Living With Robots, which is totally worth watching simply because of how well it sums up so many of the issues relevant to robotics today and in the near future: Honda’s got it exactly right: the biggest hurdle to overcome when it comes to the future of robotics is not technical,but rather an issue of public perception. At the end of the video, Mark Rowlands says “whatever robots turn out to be, will largely be a function of us, and the decisions we make.” This is an excellent point… If we have concerns about robots, it’s important to acknowledge that those concerns generally can’t, by definition, be about the robots themselves. Rather, we must understand that robots are a reflection, or perhaps more accurately a physical embodiment, of human desire, and it’s those desires and how we act on them that need to be examined. So if there are issues surrounding things like, oh, I don’t know, military robots, we need to recognize that military robots only exist because of human conflict. They’re not terminators, they’re not out to get us, they’re there because we made them and decided that they were important and necessary. This doesn’t answer the question of whether they’re a good idea or a bad idea, but the point is that you can’t look at robots as something separate from the human experience."
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THIS WEEK IN AEROSPACE

Posted by Jack Crossfire on January 29, 2010 at 10:30am
A MATERIAL THAT BONDS TO PLASTICAfter years of JB Weld, Cyanoacrylate, & epoxy failures, someone in China finally invented a material that bonds to plastic: SHAPELOCK You might even bypass the shipping costs by driving to Sunnyvale & getting it from this guy's house.http://shapelock.com/Heat it to 150F & it permanently sticks to plastic, allowing repairs to ever broken T-Rex landing gear. It can also be hand molded into arbitrary shapes. Skip the makerbot & use Shapelock to make camera mounts, sensor mounts, antenna mounts, battery holders, carbon fiber joints, fuselage brackets, servo mounts, maybe even motor mounts.Apparently it's equivalent to teflon & can be drilled & tapped. Our main use would be carbon fiber joints & propeller guards.PROPELLER SURGERY

Grinding the 3x2's down to 2.5x2's got them to last 20 minutes instead of 10 before breaking. 3x3's ground to 2.5x3's haven't broken after 30 minutes. The 2S 800mAh battery has a 10min flight time. Got used to the power management to the point where she feels like a slowly responsive copter. Unlike a normal copter, release cyclic & she sort of stabilizes in a hover.She's extremely unstable dynamically. Throttle derived attitude control doesn't seem enough for any tight position hold. She's not likely to stay inside the sonar radius on autopilot. May just put a uBlox on her & retire her.An RPM governer would be nice. Tried a simple PID loop & realized the RPM is too slow & requires too much variation to get very far. An RPM governor works best for constant, fast RPM.Got some long exposures showing position changes in no wind.

SONAR DISASTERSHaving sonar & telemetry on separate boards ended up busted. Sonar can't use laptop beacons for synchronization if the sonar & radio ground stations are on separate boards.Tried using the laptop clock but there's too much latency. The idea with clock synchronization is to broadcast a beacon from the laptop to every microprocessor to get the clock differences.With that, the Marcy 1 ground station was triple busted & we had a joyous time reverting hardware to Vika 1. It would have been better to give the Marcy 1 radio its own microprocessor & have it communicate over UART with the Vika 1 ground station.Fortunately synchronization with Marcy 1 radios works much better than XBees. The XBees added random latency.Properly calibrated sonar gives decent results.

After some sonar flight tests.

Nicely bent from water landings.MARCY-1 FIGHTS THE WINDGot some progress against wind by reducing RPM to get more horizontal thrust. Minimizing RPM gives more horizontal force at the expense of instability. Unfortunately the radio connections are real lousy & lost contact in the end. Not sure if it's having telemetry & remote control on 900Mhz or the use of dipole antennas.THROTTLE INDUCED BANKThis one shows changes in angle of attack caused by Marcy 1's throttle modulation algorithm. Not much bank because she's bolted on a test stand & also because throttle modulation doesn't cause much banking.The magnetometer derived azimuth is sloppy but flyable. The problem is modulating throttle to bank changes the RPM.Now some long exposures showing the extent of throttle induced banking.

Getting clearer that the single PWM monocopter is a lousy indoor sonar demo because of the rotor diameter & the instability required for single PWM control. A large GPS guided monocopter which spins just fast enough to stabilize pitch yet maximize horizontal thrust might work outside.

Went through many ideas for Marcy 2. A partially fabricated single fan with servo controlled vanes was busted on efficiency. A large monocopter that converts into a flying wing was busted because the CG has to change. Steve Morris did that with a clumsy tractor mechanism. Transforming aircraft certainly aren't new.A compact tri rotor using Vika 2 parts is gaining popularity for Marcy 2.M.M.M.Made a slideshow of our early flying photos with real Major Marcy Music. Apparently 1 other human in the world used Major Marcy as a username on a music service so how could we resist making a video. Maybe it was a Jack Crossfire reader.
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Developer

a 3d printed object in metal!

Posted by Randy on January 28, 2010 at 5:02am
Over the christmas holidays I got fired-up by Chris's posts on the makerbot...I didn't got out and buy one but I did give google sketchup and shapeways (www.shapeways.com) a try and designed this very complex (sarcasm) brace: http://www.shapeways.com/model/77738/simplereinforcement12.html.And then it arrived in the mail today and looks just it should. So here's a picture of it on it's own, and then with it's twin brother on my helicopter. Of course, did the heli really need it? Probably not..but it was fun making it anyway.You'll notce it's slightly bumpy but besides that it feels like normal stainless steel to me. It cost $25 including the shipping but it took almost a month to reach me here in tokyo.

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Micro Helicopter Hovering in Place Using Vision Sensing

Posted by Geoffrey L. Barrows on January 27, 2010 at 1:30pm

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Find more videos like this on DIY Drones

Find more videos like this on DIY Drones
Some of you may have seen Centeye's old website showing our earlier work flying optical flow sensors on small RC-class aircraft. Much of this work was sponsored by DARPA and the U.S. Air Force. More recently we have been hacking an eFlite Blade mCX, a very stable small 7" contra-rotating coaxial helicopter.The helicopter is a basic mCX airframe, minus the front canopy, and with the out-of-box green receiver / controller board replaced with one of our own design. Our own board sports an Atmel AVR32 microcontroller and an AT86RF230 wireless chip as well as carbon resistor strips and transistor circuits to implement the swashplate servos and rotor speed controllers. We have also integrated into the board a 6DOF IMU using standard MEMS components.In front of our controller board is a sensor ring with eight custom designed vision sensors mounted on a flexible circuit board and a processor board having another AVR32. They are stacked vertically via 0.8mm board-to-board connectors- Thank You cell phone industry! The processor board operates the eight vision sensors (which form an nice parallel system), acquires the imagery, computes optical flow, and sends high level control signals to the controller board. The whole sensor ring, including processor, flexible ring, vision sensors, and optics together weigh about 3 grams.Using a variation of control algorithms developed by Sean Humbert's lab at the University of Maryland at College Park, we were able to have this helicopter "hover in place" for up to six minutes straight. We could even perturb the helicopter slightly by manually moving it, and it would attempt to return to its original position. We have been able to get this demonstration working in a variety of room sizes and illumination levels. For these experiments, we did not use the IMU- the helicopter held its position (including yaw angle) using purely visual information. The man in the videos above is Travis Young, who has been executing the control aspects of this project at Centeye.Just to make it clear- All sensing, processing, and control is being performed on the helicopter. There is no human in the loop in these videos.Centeye is participating in the NSF-funded Harvard RoboBees project, led by Harvard EECS professor Rob Wood. As part of this project, we will be building vision sensors weighing on the order of tens of milligrams. If all goes well, we should have our first prototype at this scale by this summer!The RoboBee project will also let us do something that I personally have been wanting to do for a long time- to develop a portfolio of purely consumer/academic/hobbyist vision sensors that I can get into the hands of people like the members of this community! I'll be starting a thread soon in the "Sensors and IMUs" forum where I'd enjoy discussing this with everyone.
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Project Andromeda

Posted by Nima Kayvan on January 26, 2010 at 4:19pm

I've put together a website for a project I've been working on for 2 years now and will hopefully enter it into the Australian Outback UAV Challenge if it's held in 2010. Just wanted to post the website here for those who are interested. I'll post here when I add new entries for the blog with an excerpt for those who wish to follow the progress.Website: http://www.projectandromeda.com.auBlog: http://www.projectandromeda.com.au/blog
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3D Robotics

My Wired cover story on the "New Industrial Revolution" (including DIY Drones)

Posted by Chris Anderson on January 26, 2010 at 10:00am

One of the ways I can reconcile the amount of time I spend with DIY Drones is to think of it as a grand experiment in open innovation, which I not only participate in but also observe. That, in turn, helps me do my day job (editor of Wired Magazine) better. So for those of you who suspected that this is all grist for my next book, you're probably right ;-) This week we published my cover story, "The New Industrial Revolution" [AKA "Atoms are the New Bits"], on the broad implication of the trend of the "democratization of the tools of production" in manufacturing, which is the combination of cheap and easy prototyping tools and global manufacturing supply chains now opening to individuals and small teams. And yes, DIY Drones comes up in the story. Here's that excerpt:

"Three years ago, out on a run, I started thinking about how cheap gyroscope sensors were getting. What could you do with them? For starters, I realized, you could turn a radio-controlled model airplane into an autonomous unmanned aerial vehicle, or drone. It turned out that there were plenty of commercial autopilot units you could buy, all based on this principle, but the more I looked into them, the worse they appeared. They were expensive ($800 to $5,000), hard to use, and proprietary. It was clear that this was a market desperate for competition and democratization — Moore’s law was at work, making all the components dirt cheap. The hardware for a good autopilot shouldn’t cost more than $300, even including a healthy profit. Everything else was intellectual property, and it seemed the time had come to open that up, trading high margins for open innovation. To pursue this project, I started DIY Drones, a community site, and found and began working with some kindred spirits, led by Jordi Muñoz, then a 21-year-old high school graduate from Mexico living in Riverside, California. Muñoz was self-taught — with world-class skills in embedded electronics and aeronautics. Jordi turned me on to Arduino, and together we designed an autonomous blimp controller and then an aircraft autopilot board. We designed the boards the way all electronics tinkerers do, with parts bought from online shops, wired together on prototyping breadboards. Once it worked on the breadboard, we laid out the schematic diagrams with CadSoft Eagle and started designing it as a custom printed circuit board (PCB). Each time we had a design that looked good onscreen, we’d upload it to a commercial PCB fab, and a couple of weeks later, samples would arrive at our door. We’d solder on the components, try them out, and then fix our errors and otherwise make improvements for the next version. Eventually, we had a design we were happy with. How to commercialize it? We could do it ourselves, getting our PCB fab house to solder on the components, too, but we thought it might be better to partner with a retailer. The one that seemed culturally matched was SparkFun, which designs, makes, and sells electronics for the growing open source hardware community. The SparkFun operation is in a newish two-story building in an office park outside Boulder, Colorado. The first floor is larger than three basketball courts, with racks of circuit boards waiting to be sold, packed, and shipped on one side and some machines attended by a few technicians on the other. The first two machines are pick-and-place robots, which are available used for less than $5,000. They position tiny electronic components in exactly the right spot on a PCB. Once each batch of boards is done, technicians place them on a conveyor belt that goes into another machine, which is basically just a heater. Called a reflow oven, it cements the parts into place, essentially accomplishing what a worker could do with a soldering iron but with unmatched precision and speed. The PCBs arrive from SparkFun’s partner firm in China, which makes millions of them using automated etching, drilling, and cutting machines. At volume, they cost a few cents each. That’s it. With these elements you can make the basics of everything from a cell phone to a robot (structural elements, such as the case, can be made in low volume with a CNC machine or injection-molded if you need to do it cheaper at higher volume). You can sell these components as kits or find some college students on craigslist to spend a weekend assembling them for you. (I conscript my kids to assemble our blimps. They rotate roles, coveting the quality assurance task where they check the others’ work.) SparkFun makes, stocks, and sells our autopilot and a few other products that we designed; we get to spend our time working on R&D and bear no inventory risk. Some products we wanted to make were too time-intensive for SparkFun, so we made them ourselves. Now, in a rented Los Angeles garage, we have our own mini SparkFun. Rather than a pick-and-place robot, we have a kid with sharp eyes and a steady hand, and for a reflow oven we use what is basically a modified toaster oven. We can do scores of boards per day this way; when demand outstrips production, we’ll upgrade to a small pick-and-place robot. Every day our Web site takes orders and prints out the shipping labels. Muñoz or one of his workers heat-seals the products in protective electrostatic bags and puts them in shipping envelopes. The retail day ends at 3:30 pm with a run to the post office and UPS to send everything off. In our first year, we’ll do about $250,000 in revenue, with demand rising fast and a lot of products in the pipeline. With luck, we’ll be a million-dollar business by the third year, which would put us solidly in the ranks of millions of similarly successful US companies. We are just a tiny gear in the economic engine driving the US — on the face of it, this doesn’t seem like a world- changing economic model. But the difference between this kind of small business and the dry cleaners and corner shops that make up the majority of micro-enterprise in the country is that we’re global and high tech. Two-thirds of our sales come from outside the US, and our products compete at the low end with defense contractors like Lockheed Martin and Boeing. Although we don’t employ many people or make much money, our basic model is to lower the cost of technology by a factor of 10 (mostly by not charging for intellectual property). The effect is felt primarily by consumers; when you take an order of magnitude out of pricing in any market, you can radically reshape it, bringing in more and different customers. Lowering costs is a way to democratize technology, too. Although it’s shrinking, America’s manufacturing economy is still the world’s largest. But China’s growing production sector is predicted to take the number one spot in 2015, according to IHS Global Insight, an economic-forecasting firm. Not all US manufacturing is shrinking, however — just the large part. A Pease Group survey of small manufacturers (less than $25 million in annual sales) shows that most expect to grow this year, many by double digits. Indeed, analysts expect almost all new manufacturing jobs in the US will come from small companies. Ones just like ours."
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Developer

New 3-Axis MagnetoMeter Available (HMC5843)

Posted by Jordi Muñoz on January 25, 2010 at 12:30pm
Yes you got me, i love to make boards. ;-)The new magnetometer is pretty flexible, it will let you (through a solder jumper) select 5V or 3.3V mode, it has a 3.3V voltage regulator and an I2C translator (translate the I2C signals to 3.3V to void damage to the unit), so you are free to use it with any microcontroller (normally you don't suppose to connect it to a micro-controller that uses 5V signals). In other words is the smallest, cheapest, 5V and 3.3V, 3-axis magnetometer on the market (yet).

Another feature is that you can remove the screw holes sides in order to keep the minimum size. If you don't care about the size but you care about holding it very well then just leave as is. My recommendation for ArduIMU+ and other projects is to place it as far as you can from the any magnetic interference, you can solder a long wire all way down to the magneto board, don't worry about the noise because the i2c protocol is digital (not analog) and also the "I2C translator" acts like as a signal booster. Do you want more?

For ArduIMU+ and future ArduPilotMega Shield owners the magneto board will be pin compatible, so you can just place it on top (as the upper picture indicates), without compromising the low profile of the board:

All this for just $49.90, the same price as the SparkFun board but with more feactures. Also it works under any circumstances, thanks to its bigger tantalum capacitor (33uF).You can get yours here:http://store.diydrones.com/ProductDetails.asp?ProductCode=BR-HMC5843-01If you mix it with the ArduIMU+ it will cost $25 more than the 9DoF Razor board, but just remember that ArduIMU+ runs at 16MHz, has GPS port and you can easily place the magnetometer away from the board in case you have noisy magnetic fields close to that board that normally don't affect the accelerometers and the gyros, also the 9DoF board has I2C accelerometer that i doubt is better than the analog one we have.The advantages of 9DoF Razor is that you have Lithium Battery port, ON&OFF switch, fixed mounting holes, is $25 cheaper and soon will support our DCM code. So is up to you! ;-)Thanks for all your support!
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10th birthday of GoRobotics.net

Posted by William Cox on January 25, 2010 at 9:08am

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So, I run a robotics blog at GoRobotics.net, and low-and-behold it's been 10 years since I started it! Yikes! Time flies (autonomously?). As a way to celebrate and say thanks to all the loyal readers and followers, I contacted several robot companies (Pololu, Trossen, Apress, and SuperDroid) and got them to donate some prizes. We got lots of cools things (with hopefully more to come), and I'll be giving them away on the site over the next few months leading up to the official birthday in April. You can enter the January giveaway here: http://www.gorobotics.net/the-news/january-giveaway-10-years-of-gorobotics/There's not any aerial-specific parts, but some of the prizes could be used on a Drone (a nice 6 servo controller from Pololu, for instance). Maybe I should see if Chris will donate a ArduPilot? :)Anyway, I'm pumped about the giveaways and excited for another 10 years of blogging! Let me know what you think.
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Moderator

2010 UKAP meet.

Posted by Gary Mortimer on January 25, 2010 at 8:15am
Planning has begun for the next Southern Counties Radio Controlled Aerial Photographers meet

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That was last year, and heres a bit of David Hoggs video as well..

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UKAP/AV Meeting - 4th/5th July 2009 from David Hogg on Vimeo.

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Check out the following thread in RCG for this year.http://www.rcgroups.com/forums/showthread.php?t=1175889YellowPlane will be there with a couple of Atto flown wings and we will also have the Falcon 8 and a quad.Perhaps its just the place, even though date and time has not been sorted for a DIYdrones get together as well??Who knows, as regulations have changed so that fitting a camera makes your airframe a UAS in the UK we might manage the biggest get together of flying UAS the UK has seen. Won't be hard!Its an international meet, we had a Frenchman and somebody from Herefordshire, that's nearly Wales oh and of course Mike came down from Scotland, further than the Frenchman! He will be bringing the wine!Heres the place to look for images from last years event.http://www.rcgroups.com/forums/showthread.php?t=1075238Lots of fun, so sign up on the RCG thread if your interested. Don't tell them I sent you, I might be in trouble.G
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All in one UAV controller board

Posted by Radoslaw Kornicki on January 24, 2010 at 9:45am
Well, almost... few more things will be added in the next hardware version.This is a project that started about 3 years ago when I began building a P-47 rc airplane. Back then I decided that if it is worth doing it is also worth overdoing, so I began working on a small on board computer that would cycle the landing gear hatch doors when as it is being retracted. Since then plane never progressed forward but the simple on-board computer did.Here is what it looks like today:

and on the back:

What You can see there are:- LISY300AL with IDG500 gyros- MMA7260Q triple axis acceleration sensor- HMC6343 3 axis magnetic sensor / tilt compensated compass and additionla 3 axis acceleration sensor- SCP1000 pressure sensor - used for altitude estimate- FC30TR orientation sensor - used for calibration and in-flight attitude corrections- 4Hz 50 Channel GPS + Serantel antenna based on u-blox UBX-G5010 chip- microSD card for data logging- xBee for wireless uplink- 4 optically isolated PWM rc servo channels booth for input and output with ESD protection- SEPIC DC to DC converter - will sustain full board operation down to 1V left on the battery- high speed I2C communication expansion port- CAN communication port- all controlled from a dsPIC microAll of that on a credit card size board!Obvious things that are missing (will be added in next version):- airspeed sensor- landing gear retracts air tank pressure sensor- battery level and fuel level sensing capability (booth for electric and nitro planes)- few more PWM channels (with intended micro change, I should be able to go up to 12 pwm output channels and 6 in!)- floating point capable processor to speed up code executionCurrently the board was tested with slightly modified version of Ben Levitt's MatrixPilot code.In parallel some ground work was laid down to create more sophisticated sensor fusion algorithms through an extended Kahlman filter, so far basic functionality gives pitch and roll readings (based on accelerometers and gyros) with yaw pulled from both the compass and gps. If time allows, future version will "fuse" all of the available sensors creating a robust IMU as a base for a UAV project.
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FalconView - open source mapping application

Posted by automatik on January 23, 2010 at 9:55pm
In doing some research on ground stations, I came across FalconView - an open source pc based mapping software."FalconView is a PC based Mapping Application developed by the Georgia Tech Research Institute for the Department of Defense.The software is widely used by the US DoD and Allied countries, but historically it has not been available to the general public. Thanks to an initiative by the US Air Force, we have begun releasing a Free and Open Source version of FalconView."Guys from AeroVironment integrated it into their ground station. I came accros all this by vatching a video about Puma uav - link to video (it's in two parts, there is a comircial at the begineeing and middle of the video)Actually on EngineringTV you can find other informative videos about UAVs, robotics, and another engineering stuff.Maybe in future we'll integrate FalconView with ArduPilot GCS :)
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3D Robotics

Useful applications of amateur aerial imaging data

Posted by Chris Anderson on January 23, 2010 at 8:30pm

I'm starting to see DIY aerial photography showing up more and more often in day to day life. Here are two examples from this week: The above image, taken from a tethered blimp, is from this BoingBoing report: "Activist MIT cartographers aid Peruvian squatters": "This MIT Media Lab project worked with activists on Friday to make maps with a community of Shipibo who've taken up residence on the bank of the river Rimac in downtown Lima - a city of 11 million people. Using only helium balloons and a cheap camera, the GrassrootsMapping.org team, part of the Center for Future Civic Media, took pictures of the extralegal settlement from ~500 feet up. The images were rectified and the resulting map may help the Shipibo in their legal battle to gain deeds to the land. GrassrootsMapping.org is a project which supports communities in cartographic dispute by creating low-cost mapping tools." Meanwhile, this guy got his kite photos actually into the official Google Earth/Maps database, which is impressive indeed:

Needless to say, a UAV could have done either of these. The applications of "anytime, anywhere access to sky" are limitless!
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Results of first IMU flight tests

Posted by Magnus on January 23, 2010 at 6:06am
Today i made my first tests with a Gyro/accelerometer stabilized airframe. The system is based on an Ardupilot board and the Ardupilot expansion board with an additional gyro. The software is my own, but the Kalman filter is based on code published at the Sparkfun forum.The airframe is this 150 cm span flying wing:

In stabilization mode the ardupilot reads elevator and aileron input from the transmitter and uses this input as target roll and pitch angles. If the stick is centered the plane is supposed to fly straight ahead.The first flight tests were not a complete success. The Kalman filter seems to do a good job on the ground, but when flying i seem to get unreliable readings when turning. If i enable the stabilization et level flight it continues to fly level, but when i enable it during a turn it continues to turn rather than leveling out.My guess is that this is because the accelerators have to much weight in the kalman filter so when i make my perfect coordinated turns :) the filter is unable to keep its angles.I will keep you updated in this blog, but if anyone can give me some advice on how to tune the Kalman filter it would be appreciated./Magnus
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