Blogs

All Posts (14048)

Sort by

SLUGS AP: Fully Flight Tested and Open Source

Posted by SLUGS Team on August 31, 2009 at 12:22am

So after endless hours in the lab I am happy to report success in all fronts of the autopilot and making the GIT repository publicly available. The project's website has been updated to reflect the new hardware version and all the changes in the software. New videos have been added to our video section showing some air and ground footage.A new blog entry presents some plots of the Autopilot performance when doing waypoint tracking and the address of the GIT repository containing all the project.
Read more…
T3

UAV low altitude flight, autopilot with IMU

Posted by Krzysztof Bosak on August 30, 2009 at 11:49pm
Will it fit the meadow?

UAV low altitude flight, autopilot with IMU from Krzysztof Bosak on Vimeo.

Amateur robotic plane flying at tree level (10m above takoff point).Envelope pattern with 150-170m legs and very little error margin for anything.Only barometric altitude sensor has been used, GPS might drift too much during banked turns.Takeoff and landing in manual mode (classic RC transmitter).There was also 8m flight but the camera power died.In general altitude control band is +/-4m, 8m in windy weather worst case.NO distance ranger has been used.
Read more…
3D Robotics

A Lego PicoPilot!

Posted by Chris Anderson on August 30, 2009 at 10:00pm

The most basic autopilot you can buy is the UNAV PicoPilot N, which is basically just a one-axis gyro and a GPS, with an old Pic processor inbetween. It's a "turn-rate leveler", which is to say that it keeps the wings level with the gyro and uses the GPS to correct for gyro drift (and to handle navigation, of course). It's twenty-year-old technology, but it works well enough on high-wing rudder & elevator trainers. I've got a couple of them (which cost an incredible $700 each at the time I bought them!), and my irritation with the dated technology, high price and closed system was one of the reasons for starting this site and our projects--I knew we could do better with open source. I also have a long-standing love affair with Lego Mindstorms, which is the best robotics prototyping system out there. I've built a few Lego Mindstorms autopilots, but the truth is that for anything sophisticated it's better (smaller, cheaper and more flexible) to design custom hardware, as we've done with ArduPilot. But I've always been looking for a way to offer a Lego autopilot here that makes sense and could be built by many people. Finally, it came to me. Rather than duplicate the functionality of our full-function autopilots in Lego, why not just make a Lego version of the basic PicoPilot? So here you have it: the hardware for a Lego Mindstorms turn-rate limiter autopiliot. Basically, it's a one-axis gyro, a Bluetooth GPS (Mindstorms has Bluetooth built in and it's the best way to get serial data into it), and an ArduMUX to handle switching between RC and autonomous mode, interfaced with the NXT brick with a Hitechnic prototype board. All the functionality of PicoPilot, but open, pretty cheap, and Lego! The components are as follows (along with the NXT controller). See picture above to see what's what. --Hitechnic gyro sensor --Hitechnic prototype board --ArduMUX --Mindsensors servo driver --5Hz Bluetooth GPS (a different model is shown in the photo) Total cost of these components is around $200 (if you already have a Lego Mindstorms NXT kit), which is half the price of PicoPilot! It's no ArduPilot, but if you're into Lego it's pretty awesome all the same. Now that the hardware is in place, I'll turn to the software, modding my previous Lego autopilot code to handle turn-rate leveling. Given that this has a 5Hz GPS, I expect it will significantly outperform PicoPilot ;-)
Read more…

Replacing FMA with a 6DOF IMU

Posted by Roberto Hawkowski on August 30, 2009 at 7:22am
Hello,If I understand right, Ardupilot is dependent on FMA for roll and pitch stability.I have 6DOF IMU from Sparkfun and I want to use it to monitor the roll, yaw and pitch angles of my model airplane and use this data to perform FMA functions i.e. maintain roll and pitch stability.Sparksfun's 6DOF IMU gives accelerations and gyro data. On benchtop experiments, I can accurately measure my roll and pitch angles using only accelerometers. But, if the IMU flies in model UAV, it will be subject to all sort of other accelerations, rotations and accelerarometer readings will not be sufficient to measure roll and pitch angles.Can someone tell explain how to use 6DOF IMU to calculate roll,yaw,pitch angles in flight and eventually use 6DOF IMU to replace FMA? Do you have Arduino code for thisRob.
Read more…

Ardupilot ordered! Now for the fun adapting this to a non-rc ROV!

Posted by Aaron Buckner on August 29, 2009 at 7:57am
Hi everyone, I'm new to the community though I have been keeping an eye on this project for several months with the hopes of integrating it with my ROV Project. Last week I finally ordered my initial load out of Ardupilot gear. For starters I'll explain my project and my goals.My project is very different from anything I have seen using Ardupilot of course I could be wrong and if I am thats going to make my life easier :) My project is a PC Based Tread-Based ROV Chassis (more details here). There are several issues I will have to overcome in order to get this to work properly, Control, Data Transfer and I'm sure I'll hit a few other snags.So far on my list:The ROV isn't "RC" so I have to somehow send the control commands to the PC and then interpret them into signals the motor controller understands (currently using an Phidgets HV Motor controller).The ROV doesn't have a typical control system, no "steering" system its just like a tank, turning based on motor speed.Communicating with the Ardupilot is also going to be interesting, I'm not currently looking into Xbee as I have a wifi link to the ROV, but I'm not ruling it out, I have some short range Xbee modules I may do some testing with.Thats it for now, I know I have alot of work ahead I certainly don't think this is going to be a quick and dirty project but thats half the fun. I have an Ardupilot and the new "Main" Sensor board with an EM406 GPS unit coming next week.
Read more…

Video: UAV in a Firefight of a Different Kind

Posted by Tim Trueman on August 28, 2009 at 6:24pm
Here's a video about the University of Alaska's operation of a Scan Eagle UAV I posted about earlier:http://www.wired.com/autopia/2009/08/firefighting-uav/"Earlier this month in Alaska, a 40-pound Insitu Scan Eagle saw duty fighting wildfires after dense haze grounded conventional aircraft. The UAV is operated by the University of Alaska, which according to university officials is the first entity other than NASA and the Department of Defense allowed to fly an unmanned aircraft beyond the line of sight in civil airspace. The Department of Homeland Security also is using UAVs for border surveillance."
Read more…

First try with ardu communicate

Posted by remzibi on August 28, 2009 at 3:00pm
I am sorry for a late , but lastly I had really lot other problems so no time at all for any "flash" work .However I made few lines of code to made possible communicate sending to OSD from any external devices , so from Ardupilot also - anyway that was the base reason . HappyKillmore already wrote about it - but here detailed descryption of message format .So we can deliver information to display on OSD at location x,y looks like that :[leading character][text message][ending character][ending space]ending space is displayed always after mesasage.String to OSD shoult look like that :"$MXXYYLLEEabcd"must be end by enter character CR LF linefeed and carriage return .$M - means that it is meassage to display (M must be uppercase)XX - is a x coordinate on screen , must be hex valueYY - is a y coordinate on screenLL - is leading character hex value from font tableEE - is ending character hex value from font tableabcd - is a "text message" to dispalay (for now can be 30 char long)when LL or EE is Hx00 - then will be not displayed at allwhen text message is "" [empty] then also will be not displayedSo string to OSD can be like that in C Arduino sampleserial.println("$M050a4a4bI like that")so at location x=05 y=10 will be displaed this :" <<I like that>> "as you see LL is 4a it means [<] char and EE is 4b it means [>] char .or can be done like this way:[code]serial.print("$M") //header for messageserial.print("050a") //x and y coordinatesserial.print("4a4b") // leading and ending characters(graphics)serial.println("I like that") //message with LR CR ends string[/code]This is exactly how is working this function in OSD now .As advantage of this system when we define most significant bit of XX coordinate for 1 then we choose small fonts for text message display (only capital letters) - when is 0 then default big letters are displayed from characters table capital and small letters .[code]XX |= (1<<7) // set 7 bit for small charactersXX &= ~(1<<7) //reset 7 bit for big characters[/code]To be possible custom screen configuration , need of understanding how it is work .The screen is divided on net where the charcters are writen .The grid is 30x16 with PAL mode nad 30x12 in NTSC mode .Looks like that:[code]. X------>Y 1 2 3 4 5 6 7 8 ... 29 30: 2: 3: 4v 5. .. 15. 16[/code]So when we made configuration we just teel the program where on the screen we want first character(or graphic) of our information - up left corner is coordinates X,Y (1,1) , bottom right corner is X ,Y (30,16) - remembre that NTSC mode Y must be no more than 12 .How do we know what mode are currently in use ? - we will see after OSD init logo .I foloowed of mmormota idea about add to OSD firmware ability to display any custom information delivered by RX input at the same baud rate with GPS module .So if anyone have external device with GPS and retransmitiing GPRMC GPGGA messages , OSD can be used in usuall way - inluding autodetecting baud rate .But also in middle of NMEA messages is possible to put custoom dispaly instruction - all described detaily in post above .So here is the beta version of firmaware 1_60 - mostly for mmormota to test with ardupilot software .It is working exactly as remzibi OSD (including GPS configuration commands sent at begining by TX line after baud rate detection) plus ability to display any custom oinformation delivered by UART(com port) in the middel of NMEA messages , format described in post above :"$MXXYYLLEEabc"So with this solution there are a bit solved problem of insufficient space in OSD's chip . maybe will be possible also displaynig artifical horizon and pitch using characters E0 to E7 from character-font table .Here is my imagination of artifical horizon .Too smal chip not allowed to made it in OSD for roll - but in Ardupilot that counting can be done and using "$Mxxxxx" mesages - that should be possible - as well as pitch .a2721448-192-horizon.JPGSo for now are avaliable to firmwares for OSD , first as display termional only working without GPS named no_gps.hex and second normal OSD firmware OSD1_60.hex with ability to display anything in the middle of NMEA commands .No GPS firmware can be downloaded here - http://www.rcgroups.com/forums/showpost.php?p=12973661&postcount=1344and 1_60 firmware is already avaliable with PC software update - or here - http://www.rcgroups.com/forums/showpost.php?p=12973724&postcount=1345with pictures of possible connections .I hope that this firmware will help for many peaples doing his own project and will made poor man's OSD more open to world , also be more universal to variouse usage in many other project , not only flying platforms .
Read more…

How to change labview GCS Baudrate to 19200...

Posted by Vikram on August 28, 2009 at 6:15am
Hi all, i had to make little changes in program to get the data at 19200 baud rate...... so its all woking with wireless telemetry.. But the only problem is groundstation... how to change baud rate of ground station. Since its in labview so facing problem of changing its baud rate i have its source code also but cant get how to change.. ..or is there any software emulator to get data on 19200 and reproduce on other serial port at 57600 for GCS.. Suggestions please ..
Read more…

Remzibi's OSD now shows ArduPilot data

Posted by Paul Mather on August 27, 2009 at 9:30pm
Remzibi has released a new version of his firmware today. V1.60 includes an early version of his new messaging system that can be used for lots of other applications as well as ArduPilot.Device ConnectionOSD_your_device1.JPGFor details on the interface and more info as it develops please take a look at this thread:http://www.rcgroups.com/forums/showthread.php?t=921467&page=68#post12973661Sample Output through OSDArduRemzibi2.gif
Read more…
3D Robotics

ArduPilot sensor calibration FAQ

Posted by Chris Anderson on August 27, 2009 at 9:30am
A number of you had sensor calibration questions, so I asked Jordi, to get the answers straight from the source: 1) Are the sensors calibrated only when the bind plug is on or also with every reset? Only when you insert the bind plug, then it will be recorded in the eeprom. If you restart you don't have to calibrate again (in short periods of 15 mins, battery change for example). 2) Does the sensor calibration happen after GPS lock or before? The answer is after. The calibration happens exactly when you remove the bind plug, takes like 1 second. 3) What happens after you take off the bind plug? Any additional calibration? Well, it will read the Z sensor for calibration and store all the values in the eeprom, which takes no time at all. Just be sure the airspeed sensor is not against the wind (in strong winds). 4) Should the airplane be held in the air while the sensor calibration is going on? The airplane can be in the ground. Just stay away from the z sensor when removing the bind plug. Any other calibration tips? Always switch to autopilot when you are in ground, to see if the elevator and rudder responds. Remember that the Z sensor calibrates over time. If you leave the aircraft (even in manual) the sensor will calibrate better. Also try to apply pressure on the pitot tube to test the throttle vs airspeed.
Read more…

LCROSS IMU failure -> fuel exhausted

Posted by Jack Crossfire on August 26, 2009 at 11:00am
LCROSS IMU malfunctionIt just shows how even for the pros, something as basic as the IMU & AHRS can still ruin your day. You think it's just a matter of pimping a couple trillion dollars from the slaves, buying a super expensive AHRS to do something that's been done for 60 years & moving on to more important things like trajectory design. This is the stuff hobbyists struggle over, not multi trillion dollar space programs.But no, getting a reliable IMU & AHRS is still as fickle as ever in space travel. Unusual vibration modes, bad connections, small voltage fluctuations, RF interference, line noise all get you. We fought long & hard to minimize VicaCopter's AHRS component count down to just 3 reliable gyros & GPS because of all the failure points & the critical role the AHRS plays in our vehicles.It's tried & true technology, but it's the basis for everything. If the AHRS goes, your fuel/batteries R history. Funny how searching for LCROSS IMU on The Goog brings up the Jack Crossfire blog.
Read more…
3D Robotics

Details of Sept 2 NASA Ames field trip

Posted by Chris Anderson on August 25, 2009 at 10:00am

For those of you who signed up for the Sept 2 UAV field trip to NASA Ames and submitted your name before my comment marking the 12th person, here are the details. 1) You must PM me with your full name. You will be required to show Government-issued ID (drivers license or equiv, just like the airport) 2) Meet at 10:15 am outside the badging office in the visitors parking lot to the right of the main gate on Moffet Blvd (shown above). Please get badged as you arrive to minimize delays. At 10:30 Chad Frost will join us to escort us into the facility. 3) If you don't PM me by Friday (Aug 28th), I will assume that you can't make it and will replace you with someone on the waiting list! 4) Cameras are allowed. Chad will tell us if there's something we shouldn't be photographing. 5) We'll be having lunch in the cafeteria. You might want to bring a little extra cash for cool NASA swag!
Read more…

Multi-channel RC servo signal to RS232 converter

Posted by Roberto Hawkowski on August 25, 2009 at 2:24am
Hello All,There are many small, off-the-shelf boards which can accept TTL or RS232 serial data and control/drive multiple RC servo motor. What I am looking for is the reverse of this operations. That is, I want to measure multiple servo pulses with one small unit, and send the measured values via a TTL or RS232 port.

Do you know if there is any small, off-the-shelf solution for this?Roberto
Read more…
3D Robotics

Current standings in the T3 contest (just one week to go!)

Posted by Chris Anderson on August 24, 2009 at 9:05am

Here are the latest standings (just top 10) for the T3 contest. Our judge, Gary Mortimer, has added flags to inspire national rivalries and inter-Nordic competition. Paparazzi and AttoPilot are showing the power of mature navigation algorythms and well-turned planes, but we've got a week before the Aug 31st deadline, so perhaps some ace ArduPilot tuners will get their planes dialed in before then (I'm at the beach all week playing with config settings and flying dozens of times a day, so I may be able to improve my own time)
Read more…