Just got back from this years AUVSI Student UAS Competition. My team (Utah State University) took 1st place this year using a paparazzi based platform. We recorded the highest score in the history of the competition. It was a very fun event and my hats off to all those who put it on each year.
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I decided that I wanted to graduate from a thermopile based autopilot to a full IMU based system and the UAV DevBoard looked like it was going to scratch my itch. In the end, I wound up with it on my Multiplex Twister, an elapor foam electric ducted fan rc aircraft. Here's what I've done -One of my motivations starts with the fact that I have flown an FPV Telemaster with an Ardupilot quite succesfully but use it primarily as a failsafe. I did, however, test the waypoint system to confirm it worked. I did have to modify the gains for the aircraft but all in all, I was completely satisfied - that is until the several mornings back in the spring when we had a heavy overcast cloud ceiling where the sky temperature was equal to the ground temperature and the thermopiles couldn't see enough difference to work. (Now that summer is here in full swing, that doesn't look like I'll have that problem again for a while)Once I realized that the red version of the UAV DevBoard came in at a much lower price than the original, I took the plunge. I followed all the instructions, acquired the recommended programmer, and decided the first airplane was going to be my basically stock Easy Star with the only modification being the addition of ailerons. I compiled and programmed the board with the AileronAssist firmware and was pretty amazed by the results when just holding the aircraft in my hands. The DCM algorithm seems to work like a champ. I shook the aircraft pretty agressively, rolled it all around, and then left it propped up against the wall for about fifteen minutes and then came back and leveled it out, and all of the surfaces returned to their trimmed position. Of course, this still doesn't simulate the turning forces on the aircraft so I was going to have to hold my opinion until I actually flew.Just looking at the control surface deflections, I decided I needed more and updated both the roll and pitch gains. Now it was time to fly. Since I was mainly interested in the airplane's behavior in the "stability augmentation" mode I didn't fully test the RTL capability. So when I engaged the system in flight, I quickly discovered that putting a stability augmentation system on an aircraft that is already pretty darned stable turned out to be pretty boring. I could tell it was working, but it wasn't like it had to work too hard to keep a stable airplane level.I then realized that the UAV DevBoard would fit into my Twister with little effort. That would be a much more satisfying endeavor. So I did it, and flew it. When I flipped the switch on, I quickly realized that the gain for the Easy Star was too much for the Twister (since I didn't change it). The airplane started roll rocking with the bank angles getting larger and larger (and the roll rate going back and forth was pretty high) so I quickly turned the system off and brought the airplane in. Hey, at least this was exciting! I was out of daylight so there was no time to change the gain and get back in the air.I knocked the roll gain down (back to the original default value) and when I did get a chance to get back in the air, the wings locked solid when the UAV DevBoard was engaged. I then made what too me was an almost comical discovery - I could only bank the airplane about 30 to 45 degrees (with full lateral stick deflection on the transmitter) and when I added elevator, the airplane would tend to climb while it turned very slowly. I hadn't really thought about the difference in how you turn something like a Telemaster or Easy Star versus a Twister. The Twister moves quickly enough so that I tend to bank 90 degrees and pull on the elevator to get it to come back around. Only banking 30 to 45 degrees makes it difficult to keep in the flight area. I found it entertaining to take an airplane, that although relatively easy to fly is very responsive, and damp out its performance so that it feels sluggish. Since it is a relatively fast airplane, you can't spend much time exploring the control response before it turns into a dot in the distance. So I did a couple of passes with the system engaged, but it was only on long enough to confirm that I didn't have the patience for it to turn around and come back. I wrapped up as the sun set again and landed safely.So - I guess the next step is for me to better decide what I really want the system to do - I'm afraid if I just change the proportional roll gain back up so that it will allow a 90 degree bank angle, I'll get the roll oscillations again. I'll have to think about whether or not a PI control loop will cut it and if not, will a PID system solve the problem.Not knowing when to leave well enough alone, I'd like to be able to add some telemetry and an airpseed sensor so those bring up a question. My understanding is that the spare dsPIC pins that are available are digital and do not support any A/D conversions. If that is true, and if I want to integrate other sensors, I'll need to have another processor do the A/D conversion and send that data to the RX pin of the unused/debugging USART. And when I'm ready to send telemetry, I can use the transmit pin on that USART. That sounds great except...I'm not sure how to make the second USART work. It appears to be set up in the AileronAssist software to write debug data, but if I hook it up to an FTDI cable and monitor the serial port, I get nothing. When I put an oscilloscope on the Tx pin I get nothing. Is there something I'm missing?Regardless, this hobby sure provides me with the ability to tinker, tinker, and tinker some more, which is exactly what I enjoy.
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I failed to get the waypoint utility to read and write to the board, and read the comments on the blog.So I want to put them in manually, but the manual says to put them where it says "wp-lat wp-long I cant find these in the code. I am running 2.2.3
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With more and more small drones being put into the air by the military, companies, individuals like us we will start to see more incidents like this one;
Granted, the owner of this RC plane also designed it to look like a hawk, but the military will probably start to camouflage small drones to look like birds to draw attention away from low-level flights. Have any of you experienced situations like this? I know the WowWee Dragonfly already had this issue.Source: JalopnikSource: EngadgetRead more…T3
AXN FloaterNot sure if any of you have seen this, but there's a decent looking easy star clone for what appears to be a pretty good price. Here is a review.The shipping will be a little steep at about $35-$40, but considering it comes with a brushless motor, speed controller and servos for elevator, ruder and ailerons the price isn't half bad.I'm looking for a airplane test bed for the PicPilot so maybe I'll order one up and be the Guinea Pig on this one.Brian
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Hi everyone, Ive been a member here for a while and though Ive gotten a lot out of following along with all the great projects here, I havent really had much to contribute back (aside from referring friends). Well now I do! I posted this over at the arduino forums but I figured it would have a lot of impact here too: I have successfully read the gyro data from the Wii Motion Plus peripheral. I posted code and some additional info on my shiny new blog: hereand if someone can tell me how to post code on diydrones, I'll gladly post code here too.
I received my u-blox GPS receiver and connector from Sparkfun recently, and needed a PCB to hook it all together. I've put together a simple layout including a lithium backup battery and a 4-pin 0.1" header to connect it to my ArduPilot.I've attached the Eagle file for the layout. I case you don't have Eagle, you can get it free at www.cadsoft.de. I've also attached two PDFs, one with labels, the second with only the traces and pads, mirrored to use for toner transfer. This is such a tiny board that I didn't want to send it off to be made, so I used to toner transfer method to make a quick prototype. I didn't have the proper transfer film, and used inkjet photo paper, which didn't work great, but was good enough for a first prototype.The GPS connector is a bit tricky to solder on, but if you have some experience with surface mount soldering, it is not much different than a fine-pitch IC. You might want to order a couple of extra connectors in case they get damaged, they seem pretty delicate. I chose to not use to backup battery at this time, and connected a jumper wire from the positive pad for the battery to the 3.3V supply. The correct battery for the PCB is part P244-ND from Digikey. It was tabs attached to the battery to allow it to be soldered to the PCB.The GPS connector does not provide a good mechanical connection, so the breakout board must somehow be attached to the GPS receiver. I used double-sided tape for this.After connecting power to the board and hooking it up to the PC with a 3.3V FTDI adapter, I successfully connected to the receiver with the u-blox software, and got a GPS lock. Now on to getting it working with ArduPilot!Note: This is a single sided board - the GPS connector mounts on the top (copper) side, while the 0.1" connector and battery mount on the bottom. You must take care to ensure that the battery lead does not extend far enough to touch the receiver PCB (and possibly short something).UPDATE: I've temporarily removed the PCB files. The way I had the TX/RX pins on the board was swapped with respect to the ArduPilot, so I am fixing that, and will post new layout files soon.
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If you're confused about why your ArduPilot 2.2 isn't putting your EM406 into binary mode when you've got the setup jumper/bind plug on (symptom: the yellow LED doesn't blink a few times on start, the GPS LED stays on and the blue ArduPilot LED won't stop blinking), it's probably because you didn't tell the software that you're using the EM406.
In the original EasyStar.h file, this line was set to default to the uBlox module (2):
//1-7
#define GPS_PROTOCOL 2 //0 = NMEA, 1=SIRF, 2=uBlox, Choose protocol, uBlox only for PRO's please.
The manual says to change it for your GPS, but it's easy to miss. Given that the EM406 is the recommended GPS and we say uBlox is only for pros, this wasn't a good default. So I've changed it to default to EM406 (1), so the code on the Google Code repository now has the following line:
//1-7
#define GPS_PROTOCOL 1 //0 = NMEA, 1=SIRF, 2=uBlox, Choose protocol, uBlox only for PRO's please.
Hopefully, this will solve the problem for those of you who were confused, and avoid more confused people in the future.
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The emulator running some demo data, and showing the result.
The Bluetooth/GPRS application I've been working on is now functional enough that it might be of use to someone. Feedback and suggestions are appreciated. Currently, the application has been left as a dumb bent pipe, so the mcu has complete control over the data stream (though it must conform to the var1=xxx&var2=yyy......\n format for parsing to work, see code and documentation).Code here bb.zipDescription:BlueBot is a bridge between Bluetooth and HTTP. Bluetooth's Serial Port Profile (AKA RFCOMM) is a streaming protocol that acts like a serial port. Due to carrier gateway restrictions, streaming network sockets are often impossible, so HTTP is used. HTTP is not streaming, so BlueBot listens for \n's in the SPP data stream to separate packets. Each packet is then forwarded to a remote server, returning a response that is streamed back over Bluetooth.Use:The UI is rough, and the program surely has bugs. I'll be tidying it up - adding a live display of data, etc... The application was built for the lowest common denominator of phones, so it should work on almost any phone that has JSR-82 and some sort of data capabilites. Be sure to install the PHP script on an accessible IP or else handshaking won't work.The general use is:-Start application-Set up network--Handshake with the remote server-Set up Bluetooth--Search for devices--Connect to a device-Run (Both Bluetooth and Network have to be setup before this)-DisconnectInstallation:I can't really offer any advice on the installation onto the phone - I am very new at this. It has been tested on 2 Blackberry phones and on the Sun ME emulator. It is an unsigned application, so it has to at least ask for permission to use Bluetooth and the network, or it might not even be allowed to install on some phones.Contents:BlueBot.java - Handles program flow and UI elements.BluetoothConnection.java - Bluetooth utilitiesNetworkConnection.java - HTTP Utilities and the network send threadReceiveThread.java - Reads the Bluetooth input and condenses them into packets for SendThread.SendThread.java - Sends packets over HTTP and sends the responses back over Bluetooth.SPP.java - A MIDlet that simulates a Bluetooth device to communicate with. Just prints some test data at 1Hz right now.kmlupdate.php - A slightly updated PHP script that parses incoming data. It doesn't return anything yet except for the handshaking phase.
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I shall use this post to add some descriptions about my ArduPilot airframe, the SIG Kadet Senior BIY kit converted electric. I'll add tids and bits of this work in progress started last autumn once in a while, when timetable permits.
As a starter, I think it's interesting to say that this airframe now flies! I maidened it this last sunday and I must say, after three flights and excepting a little mishap on the third landing approach, I am more than happy with the result and glad to go on with developing to a full ArduPilot platform.But for now and before I expand this post, here a short video of the first maiden takeoff.
Next is a short footage of the second maiden takeoff illustrating that e-power is fine and plenty. I run a 560 RPV brushless outrunner, a 100A ESC, a 6 cell lipo battery with 9000 mAh capacity, all of Chinese manufacture (the lipo is a custom order, though). The propeller size a 11x7''.Next video is showing some aerial action. I am not a good pilot, so do not expect perfection here...By the way, I wish to thank my colleague and friend Claude for having handled the camera that maiden day.More is to come, so stay tuned!---------------I worked on preparing ArduPilot and other components like my pan & tilt video camera, my "Nunchuck Headtracker", and my OSD. As I have written in another post, I intended to have a spare ArduPilot board (old version) used only for Xbee reception from headtracker/photo shutter and, additionally for parsing data needed by he OSD. I struggled a lot with multiple instances of NewSoftSerial to handle the data flux. After some rethinking, I decided to simplify the setup and processing by this spare ArduPilot board. So I included an Arduino Pro Mini (3 computers in the plane because I am a too bad coder!!!!). The spare ArduPilot will act as Xbee reader, pan&tilter for the cam, and photo shutter for the 10Mpixel digicamera. the additional Arduino Pro Mini will just receive data from the autopilot (ArduPilot 328) and parse what is needed to the Inspire video OSD. So I need no soft serial in the chain of operation. Since I made the step adding the Arduino Mini, everything runs as expected.The photos will be taken down vertical from a bay inside the fuselage. The Kodak digicamera stays in place with small strong magnets (easy to take out and very precise lock in place) and is activated mechanically by a 5g servo (I did not hack this camera for electric shutter yet as I've done with a preceding 5Mpixel before). The shutter servo is linked to the OSD which has a shutter connector and can be programmed to do time lapsed shot. the cam is slow to store high res pictures (about 4-5 seconds each), so I programmed the OSD to take a shot every 10 second. The OSD will write the GS location and a autonumber to its memory with every shot, which is nice. It also has a shutter input connector for RC triggering. So I will connect this input to the spare ArduPilot (pan&tilt&photo) on its 3rd servo channel, so I'll be able to trigger pics with the Nunchuck handle in between time lapsed photo shots. I'll modify my code for this additional function tomorrow evening, because it came to my mind today that I can actually combine time lapsed and manual trig. Before I thought I had to chose between both solutions.So all this is not much about the Kadet Senior. On the airframe itself, I've mounted my video transmitter with antenna. It is in the middle of the fuselage, just behind the wing trailing edge bolts. Tonight I've also mounted the small microphone (with basic amplifier) I got from Hong Kong through Ebay for a pair of bucks or so. To isolate it a bit from the noise and air flux inside of the fuselage (needed in an E-converted plane to keep things cool), I decided to follow a suggestion from a colleague and mounted the microphone inside a ping-pong ball! I cut open a triangular hole in such a ball with my acto knife, kept the triangle, stuffed some make-up cotton (thanks to my wife) inside the ball (not too much, not too tight, though), inserted the microphone tip to the ball center and glued on the cut to shape triangle door with some plastic modeling glue (the one that smells like my childhood!). On two opposite sides of the ball I glued some folded piece cut out from another ball and could finally mount the microphone ball in the tail part of the fuselage behind the control servos, far from the motor and prop noise. I used to elastic bands attached to the folded slots to finally have the ball with no direct contact to hard and vibrating fuselage parts. Maybe I will hear the sky instead of just the engine!!! Or maybe not... we'll see.Promised, tomorrow I'll do some pics to illustrate all that for those who don't like or have time reading long posts.And i the future, when time permits, I'll try to give some more details about solutions adopted for the airframe (tray for the 1.3kg lipo battery, cooling hatch for the ESC, double switch to avoid sparks when powering up, video battery in the wing to counterbalance pan&tilt camera, electric wing connections through RS-232 connectors, etc.---------------For those interested in Xbee RSSI signal monitoring in Arduino/ArduPilot, I've described what I've just implemented in my setup in a separate post.---------------
Read more…3D Robotics
Centripetal force compensation is a algorithm than compensate centripetal forces effect over accelerometers so AHRS could get a correct attitude measurement during large turns.we are using a simple record player to test centripetal compensation.Effect of centripetal force could be a problem if the plane stay in a turn for a large time, for example doing circles.jlcortexnmine.com
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The Vectornav VN-100 IMU (they call it an Attitude Heading Reference System, for some reason) is out and it looks like the best device on the market in this price range. Here's the description from the site.
The VN-100 combines a 3-axis accelerometer, 3-axis gyro, 3-axis magnetometer, and a high performance processor onto a single surface mountable chip-sized module to create a high performance orientation sensor. Fully calibrated for bias, gain, and misalignment, the VN-100 accurately calculates orientation over the entire 360° range at 200 Hz. Filtered orientation data and inertial measurements are assessible via either a SPI or RS-232 serial interface.
With its small size, high performance, and low cost, the VN-100 has numerous potential applications. A development kit is available for the VN-100 which comes with a sensor pre-installed and gives easy access to all of the sensor's features.
Features and Benefits:
Complete Sensor Package
3-axis accelerometer
3-axis gyro
3-axis magnetometer
Multiple Output Types
Heading , Pitch, Roll
Quaternion / DCM
Acceleration, Angular Rates, Magnetic
High Precision
Heading accuracy < 1.0 (static)
Pitch/Roll accuracy < 0.5 (static)
< 3 deg dynamic
Fast Onboard Processor
Extended Kalman Filter
200 Hz update rate
Surface Mount Package
Hand solderable
30 pads
Ultra-Compact Size
22 x 24 x 3 mm
3 grams
Fully Calibrated
Scale Factor and Gain
Axis misalignment < 0.05 deg
Hard / Soft Iron Compensation
Digital Interface
Serial UART up to 921600 bps
SPI Interface up to 18 MHz
Low Cost
$400 - 500
*Price depends on quantity
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Given that ArduPilot is now in a relatively mature commerical release, it's time to reset the comments on the home page. Rather than delete the 400+ comments (dating back more than nine months) on the old home page, I've just created a new home page with the same info, so we can start the comment thread anew. The old one is still here and all comments will show up in any searches on the site, but newcomer will not be confused by old conversations about bugs long gone.
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I didn't expect that fast response on uploading a picture otherwise i would have included a little more information. As i didn't know if anyone read it if i commented on my own picture, i figured i should make it a blog post.The picture was ment to be a reference of a prior project. I am currently looking for videos or fast image sequences taken onboard a UAV. The goal of that is to evaluate the feasibility of some computer vision algorithms for use onboard a UAV. I wrote a post in the forum about it and would be super glad for any data provided by this community. In return i'll keep you posted about any progress. (in case there is none and it would be too embarrassing i might not ever mention it again though)
The board is a stereo vision system for mobile robots i designed two years ago. Due to the four layer board, rather good lenses, and custom made lens mounts it's worth around 500 Euros paid for by the Hamburg University of Technology (It was before i spent my year abroad in Berkeley. Unfortunately i'm back home again.) The distance choice was rather random, designed to fit on a euro board (100 x 160 mm) and for rather short distances as the mobile robot was intended for indoor use.Some specs:-It uses two identical VGA Kodak CMOS image sensors-A Spartan3 FPGA with 32 MB of SDRAM and 4 MB of SPI Flash drives the image sensor and is intended for some low level image processing (like undistortion etc)-A Blackfin BF532 (you were right) running at 400 MHz with 32 MB SDRAM and 4 MB SPI Flash then does the stereo processing of the image data-Computed data is transmitted over ethernet using some Microchip SPI LAN controller-board is four-layer as mentioned, lens mounts are custom made CS mounts, the lenses have a fixed 4 mm focal length-The power consumption is moderate. The FPGA and the LAN controller burn relatively much power but it's still a dimension you might provide with batteries.Here some results. I know they are not brilliant but it's just the first attempt with a rather simple algorithm. (I added them anyways as it wouldn't be complete without it) Brighter gray corresponds to closer Objects.
A note about that kind of stereo vision for use in UAVs: I might be wrong, but to me it seemed like a not so feasible approach due to the relatively high distance to objects on the ground. The base length needed to get reasonable spatial resolution even with high resolution sensors would probably be too large (even if the two cameras were mounted on the tip of each wing). I'm trying to dive deeper into structure from motion techniques with one camera hoping to get some results while keeping the overall system complexity about the level of an ambitious hobbyist project.Bye, Jørn
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I have loaded 2.2 onto the Ardupilot and put the jumper on to set the gps to binary and home position.The blue led blinks fast but never gets a lock, it used to work before I/ tried to set it to binaryPaul
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