This flight we wrapped an altitude hold control law around the attitude tracker flown on Flight 22. This one should hold the altitude at the level the pilot engages the auto flight control laws. It also holds wings level and airspeed at 23 m/s. Visually we observed the aircraft descend and the pilot had to disengage the control laws early. Looking at the data, we see the elevator saturate to bring the nose up and it looks like we ran out of control authority. All other aspects of the control law appear to be working well. As a reminder 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. For future flights we plan to modify the auto flight control laws to use L4/R4 as an elevon, which should provide much improved control authority.
Fenrir Flight 23.
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