Finally, it's done... My tricopter flies along a three-dimensional path without me doing anything. The waypoints are recorded by some sort of "teach in" (basically taking snapshots of different positions in space, the flightpath is hence calculated as the cubic interpolation between these snapshots). Principle: A web cam (mounted to the ceiling) tracks 4 IR-leds that are installed on the copter. My computer then calculates height, yaw, x & y shift of the copter, as well as velocities and accelerations in all directions. Commands are subsequently sent via a wireless serial link to the tricopter. I want to thank watterott.com very much for donating two XBee radio modules for the wireless RS232 link!
Watch these videos for more infos on the LED tracking procedure:
Check my blog for things related to the tricopter:
(updated with the source code of the matlab tool)