Fenrir Flight 21

Fenrir flight 21: Launch video can be found here: https://www.flickr.com/photos/100936386@N02/18175199185/in/dateposted-public/ This flight we tried an attitude tracker on pitch and roll angle as well as an airspeed hold. The gains on p and q were tuned to zero. One thing to keep in mind here: when the pilot is flying, he is using L2/R2 as an aileron, L3/R3 as an elevator, and L4/R4 as an elevon. For the auto flight control laws, I wrote the software to only use L2/R2 as aileron and L3/R3 as elevon, leaving L4/R4 and L1/R1 at zero. The excitation was a doublet on phi command followed by a doublet on theta command. The pilot disengaged the autopilot shortly after engaging - we were expecting the aircraft to roll left first and then right, so when he saw a right roll he toggled out. With respect to the theta tracking. We can see the aircraft working to maintain the commanded zero theta when mode is 2, which means the auto flight control laws are engaged. With respect to the phi tracking, you can see why the pilot toggled out as roll angle got up to 50 degrees to the right. The Ultra Stick aircraft use an unconventional sign for positive aileron and we had a sign error in our phi tracking control law. Easy enough to diagnose the problem. We found the throttle working slightly to maintain 23 m/s and it appears to be working pretty well