ArduPilot (Legacy) main page

[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

The code is not difficult to modify if you take the time to go through it and build an understanding of what it is doing, and you can read a reference resource for the C language.

A couple things to note. The 4th servo output is currently not implemented, and doing so will involve a minor hardware modification and some programming involving interupts, which is not beginner level programming.

Also, on the question of flight at 75 degrees nose up - as you approach 90 degrees use of separate aileron and rudder input becomes important for stable flight. The ArduPilot code is written to use either aileron OR rudder control, not both. Changing it to use both in an independant manner will be a somewhat involved change to the program, in addition to the hurdle of implementing the 4th servo output. It can all be done, but may be beyond reach of a beginning programmer.

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Comments

Robert Batson November 6, 2009 at 7:52pm

What additional circuitry is needed to initiate specific actions at given waypoints - for example, dropping a marker?
Infinite Aerospace November 6, 2009 at 8:04am

Thanks Doug! I am going to have to come up with something. Still in the design stage of the aircraft, considering my auto pilot options.
Mike Bakula November 6, 2009 at 6:34am

Doug, what hardware mod is needed for the fourth servo out? It appears to be wired...
3D Robotics

Chris Anderson November 5, 2009 at 9:39pm

Joe, thanks for the catch. No idea why that slash went missing, but it's now fixed.
Developer

Doug Weibel November 5, 2009 at 5:41pm

The code is not difficult to modify if you take the time to go through it and build an understanding of what it is doing, and you can read a reference resource for the C language.

A couple things to note. The 4th servo output is currently not implemented, and doing so will involve a minor hardware modification and some programming involving interupts, which is not beginner level programming.

Also, on the question of flight at 75 degrees nose up - as you approach 90 degrees use of separate aileron and rudder input becomes important for stable flight. The ArduPilot code is written to use either aileron OR rudder control, not both. Changing it to use both in an independant manner will be a somewhat involved change to the program, in addition to the hurdle of implementing the 4th servo output. It can all be done, but may be beyond reach of a beginning programmer.
Infinite Aerospace November 5, 2009 at 3:42pm

Thanks for the input so far. The vertical component would be nose up. I think I will have to research into this more, programming and electronics are not a strength for me. Any idea how difficult it is to edit the code?
Infinite Aerospace November 5, 2009 at 2:41pm

Question re: Ardupilot 2.3:

In the features section about it is stated; "Four RC-in channels (plus the autopilot on/off channel) can be processed by the autopilot. Autopilot can also control four channels out."

Does this mean the ardupilot can control 4 addition channels on top of aileron, elevator, throttle? If so can these channel functions be triggered by a specific GPS waypoint? For example at a specific gps waypoint could speed brakes be activated?

Finally does anyone know if the Ardupilot is capable of guiding a near vertical (~75deg) flight path?

Any help or enlightenment would be greatly appreciated.

Thanks in advance!!
Joe November 4, 2009 at 11:05pm

I downloaded ArduPilot24 from googleCode and attempted to compile it. The compile failed, after some debugging I found that there is a missing "/" in easystar.h, line 139. This causes the variable to be corrupted.

Hope this was helpful and posted in the right place.
Greg Gibbons November 2, 2009 at 7:36am

Labview compiles as you write the code, that is one of the nice features of Labview, test as you write. As long as the application is on the computer you have Labview installed on you can run your app any time without the application builder. The application builder is only needed if you want to distribute executables to folks that do not have Labview installed.
Greg
Developer

Doug Weibel November 2, 2009 at 6:41am

Earl,

Can you elaborate? If you cannot compile an exe how do you use it? Can the runtime engine compile from the source?

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