[This original ArduPilot board, now called the "Legacy ArduPilot" is no longer produced or officially supported by the DIY Drones dev team, and this page is maintained just for historic reasons. However, there are still many users of it out there and it still works fine. The user group for Legacy ArduPilot users, for both thermopile and IMU use, is here.]
ArduPilot is a full-featured autopilot based on the Arduino open-source hardware platform. It uses infrared (thermopile) sensors or an IMU for stabilization and GPS for navigation. It is the autopilot used to win the 2009 Sparkfun Autonomous Vehicle Competition.
The hardware is available from Sparkfun for $24.95. An expansion board ("Shield") kits that includes an airspeed sensor, a 3.3v power regulator for 3.3v GPS modules and other sensors and cables and connectors for easy attachment of the XY and Z sensors, is available from our own store for $57.20.
User f
ArduPilot features include:
- Can be used for an autonomous aircraft, car or boat.
- Built-in hardware failsafe that uses a separate circuit (multiplexer chip and ATTiny processor) to transfer control from the RC system to the autopilot and back again. Includes ability to reboot the main processor in mid-flight.
- Multiple 3D waypoints (limited only by memory)
- Altitude controlled with the elevator and throttle
- Comes with a 6-pin GPS connector for the 4Hz uBlox5 or 1hz EM406 GPS modules.
- Has six spare analog inputs (with ADC on each) and six spare digital input/outputs to add additional sensors
- Supports addition of wireless modules for real-time telemetry
- Based on a 16MhZ Atmega328 processor. Total onboard processing power aprox 24 MIPS.
- Very small: 30mm x 47mm
- Can be powered by either the RC receiver or a separate battery
- Four RC-in channels (plus the autopilot on/off channel) can be processed by the autopilot. Autopilot can also control four channels out.
- LEDs for power, failsafe (on/off), status and GPS (satellite lock).
Resources:
ArduPilot requires the free Arduino IDE to edit and upload the code to the ArduPilot board.
The code is currently optimized for the Mutiplex EasyStar three-channel powered glider and FMA sensors, but can be modified for other aircraft and sensors. It uses the rudder/ailerons and elevator to maintain level flight and navigate to GPS waypoints. It supports a desktop setup utility and ground station software. It also includes a "fly-by-wire" mode that simply stabilizes RC flight. The main code is ArduPilot2.x.zip in the download section of our Google Code repository, where x is the latest version.
What you need to make a fully-functional autopilot:
- ArduPilot board
- Shield expansion kit with airspeed sensor
- GPS module (uBlox5 recommended)
- XY and Z sensors or ArduIMU+
- FTDI cable for programming
- [Optional] Two Xbee modules for wireless telemetry. This one in the air and this one with this antenna on the ground/laptop side. You'll also need two Xbee adapter boards. You can connect the airborne Xbee adapter to Ardupilot Mega with jumper wires.
Open source extras:
- If you want to build your own board from scratch, the necessary files and component lists are here.
- [Note: you shouldn't need this, since this code is loaded on the ArduPilot board at the factory] Latest multiplexer code (for the board's second processor, an Attiny, which runs the failsafe system) is here.
Instructions for loading this code are here.
Recommended UAV setup:
Airframe option one: Hobbico SuperStar (49" wingspan, $95, shown above). This is an inexpensive, good flying high-wing trainer with ailerons. It can be hand launched in a park or take off from a runway, and replacement parts are readily available in case of a crash. If you want much better performance with this aircraft, you can upgrade it to a brushless motor, speed controller and a LiPo battery. [If you don't already have one, you'll also need a balancing charger and power supply.] Note: any stable aircraft with both ailerons (for stabilization) and rudder (for navigation) can work, so feel free to experiment with what you've got.
Airframe option two (recommended for ArduPilot 2.x): EasyStar (shown above). Performance can be improved with the modifications described in this post.
You'll also need:
- A six or seven channel RC transmitter and receiver, with at least one toggle switch (ideally three-position but two-position will work, too, although you will have to mix channels to have access to both autopilot modes in the air), such as the Futaba 7C.
- Some servos (at least three for ArduPilot 1.0; at least two for ArduPilot 2.x) and at least three female-to-female servo cables to connect the RC receiver to ArduPilot.
Cool optional extras for your UAV:
- A GPS logger to record your mission and play it back in Google Earth
- A tiny video camera to record the flight
- A wireless video setup to see realtime video from the air
Comments
If it compiles OK but does not load then, yeah, you may need to burn your boot loader again. There is alot of support in here for fixing a corrupted bootloader - sometimes happens when you power on the Ardupilot with XBEE connected.
Hope this helps
I use the sparkFun FTDI, and I have uploaded the code many times to the board. The problem came after I try to use Eclipse IDE.
Thanks.
What connector are you using for FTDI? Cable or Sparkfun board?
I would suggest that you try loading a very sinple program like the BLINK demo which will flash the LED on pin 13. Once that loads then you can try Ardupilot firmware.
Ardupilot takes a long time (about half a minute) to compile so it can give you the impression tat something is wrong when everything is OK.
Hope this helps.
After I try unsuccessfully to use Eclipse IDE for programing Ardupilot (like here), I discard this option and back to the ardunio IDE, but I get the next error trying to upload the code to the board:
"avrdude: stk500_recv(): programmer is not responding"
and the red LED is alwais fixed to ON, even if i push the reset button.
Realy, Eclipse IDE never compiled the code without errors, so I think it nerver tried to upload anything to Ardupilot board (but i'm not sure).
I think i need to burn bootloader, any other suggestión.
Thanks.
I used a "0" value for CH3_TRIM but I set the radio values every time I fly. There is a setting in the header file for this. There is also a utility for reading your radio values so you can hard-code them later.
My Ardupilot tends to reset (meaning restart the program) when my switch is in the middle position. If you are looking at the serial output with the Ardupilot connected to your computer it will show a reset by restarting - It will say "Ardupilot 2.6 beta" and print out some initial settings like waypoints and home position. Your Blue LED will also turn off for a while. I solved my problem by using a 2 position channel (my landing gear) for the mode input. Resetting can be caused by low voltage to the Ardupilot or electrical noise from the serial communications.
As far as the downward tendancy, it sounds like your plane has a good CG.
I think you need to use negative values to compensate for nose down. Perhaps you could try different PITCH_TRIM values and see what you get when the plane is in a level position.
Do you have any telemetry? e.g. XBEE connection? I have found it a lot easier to fix my IR (ROLL, PITCH) when I am outdoors. I do my adjustments outside and record them on a laptop in my car. I guess you could use some long wires if you don't have the XBEE's. Some CAT5 computer networking wire could give you a nice connection from the FTDI cable to the Ardupilot. That way even a home desktop computer could work if you hang the wire out the window. I realize that we are an International community and some of our members do not have access to a laptop computer.
Anyway, I'm interested to see if this works for you.
When I turn ON the STABILIZED MODE the plane starts to have a pitch down tendency compared with the MANUAL MODE. Basically the plane does not have this nose down tendency while I fly in MANUAL MODE.
Florin
What do you mean by Ardupilot re-setting?
What should I look for in the output of the Ardupilot during the bench test?
Last question :-)
What value did you use for #define CH3_TRIM? I see in the code that they put it to 0 as default but they mention that one can use the actual microseconds value... How can one find this value?
For the PITCH_TRIM I guess that I should use positive values (+3; +4 etc.) in order to correct for the nose down tendency... is this guess correct?
Thanks,
Florin
Florin, I'm no expert but perhaps you could check your IR sensor settings, too. Field calibration takes some getting used to. I try to hold the plane with the IR sensors away from me since body heat throws off the readings. Then I keep each window pointing to the sky for a few seconds. When you return the plane to the normal position the rudder and elevator should be centered and respond as expected to correct for Pitch and Roll. Again, I try to keep the plane away from myself by holding it above my head.
PITCH_TRIM can be used to correct for the pitch down error. You may also want to try moving your battery forward or backward to change the CG - this should be tuned in MANUAL mode.
As far as the Throttle signal goes, STABILIZED MODE should give a nice linear response to your Radio. FLY_BY_WIRE is where the Ardupilot tries to compensate for Altitude change with elevator and throttle.
Perhaps your Ardupilot is re-setting? You may want to do a bench test and look at the Ardupilot output on a computer (Be VERY careful about the prop spinning up ESPECIALLY in FBW or AUTO). I use the XBEE wireless for field tests and send the output to "Terminal" for capture.
Let us know how it goes!
I did first flight tests with Ardupilot (code 2.6) in STABILIZED MODE with throttle connected directly to the receiver.
When I switch STABILIZED MODE ON I notice that the plane starts to fly but with a increased tendency of pitch down. Can I correct this by using the PITCH_TRIM variable in the header file?
Florin
Has anybody flown with Ardupilot code 2.6, ardushield blue board in STABILIZED MODE with throttle control through Ardupilot?
I try to do this but I get variable throttle output on the test bench. Basically I switch to STABILIZE MODE and when I push throttle stick up the motor would go with various rpm's. The motor rpm is oscillating. Is this normal behaviour?
I don't get this behaviour in MANUAL MODE. In MANUAL MODE I get normal throttle behaviour. I move throttle stick up, then I get increasing motor rpm but NOT oscillating...
Thanks,
Florin
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