Last weekend our team from Robotik AG Ilmenau won the RobotChallenge AirRace in Vienna, sharing the winner's podium with team "Sirin" from russia.

Both teams could complete 24 rounds in 10 minutes!

Our UAV is based on the Exynos 4 Quadrotor using 2 cores for opencv image processing and one for executing the flight code.

After our "safe trial", we increased the flight speed but unfortunately our attempt ended in red smoke (motor controller died).

The video below shows a quadrotor following bilinear interpolated SRTM elevation data. Pitch, roll, yaw are controlled manually.

Barometer and elevation readings are zero'ed at start.
The baro setpoint is set to a safety distance of elevation + 7m.

There are basically three Linux processes involved in this: The GPS publisher passes latitude/longitude data to the elevation map lookup service, which publishes elevation data to the autopilot. This communication is implemented using ZeroMQ. The GPS and autpilot services are implemented in C, while the elevation map is implemented in Python.

The interpolation of SRTM data can be found here:
https://github.com/PenguPilot/PenguPilot/blob/master/elevmap/service/srtm.py

Note: There are some "jumps" in the altitude, which are caused by wind gusts or lateral movement commands, affecting the imperfect altitude controller. Some more tuning is required here.

Raspberry PI Quadrotor running PenguPilot on Linux

A picture of our UAV:

The electronics:

Our software: https://github.com/PenguPilot/PenguPilot

We use the Odroid U3 to control a quad-rotor (no microcontroller-based flight control, just plain Linux control code). As a Linux distribution on the ODROID we use Gentoo, and of course our quadrotor natively compiles all of its software (kernel, userspace)
Please have a look at our first operating prototype:

A more detailed picture with annotations is provided here:

As you can see, on top of the U3 we use the IO shield from ODROID. The U3 io shield is programmed with a simple firmware similar to FirmataC, which:
- parses PPM RC receiver signals and sends them to ttySAC0
- reads pwm outputs from the autopilot via ttySAC0 and generates the PWM signals.

Some additional electronics, including power supply, logic level converters and a I2C IMU (MPU9150 + MS5611) sensor are placed on top of the IO shield. The GPS receiver is connected via USB and we have WiFi and a Webcam connected to USB as well.

The software for controlling the UAV is called PenguPilot. It is freely available via Github here, but the documentation is in an early stage: https://github.com/PenguPilot/PenguPilot

Stay tuned for the next update (in-flight video) and do not hesitate to contact me.