Log & Flight Analysis Assistance

🧪 Flight Testing & Log Analysis
1

Opterra 2m using FX-79 Buffalo Flying Wing airframe.
Pixhawk 2.4.8
Wind from the East about 5-10 mph
Flight Log

  • FPV video showed it kept bouncing up and down but winds aloft weren’t really strong or gusty. In the log graphs, the Pitch Estimated and Pitch Rate Estimated are way over both Pitch Setpoints. For a smooth flight, assuming fairly smooth air, I’m presuming the Estimated should be in line with Setpoint? What params should be adjusted and to what value?
  • The same goes for Roll Angle and Roll Angular Rate but it was not as jerky as the Pitch.
  • What could’ve caused the logging to quit just a little over 4 minutes into the flight? There was plenty of free space in the SD card.

The education is highly appreciated.

2

Looks like you are not flying with an airspeed sensor? Just want to confirm. If that is the case TECS is operating in non-airspeed mode. I have limited experience with this mode, but I’ve seen it behave more aggressive in pitch sometimes. There isn’t really a way to accurately know airspeed so gain scaling isn’t the best with this mode. I don’t see anything obvious as to why the log stopped.

3

That’s correct, no airspeed sensor. Notwithstanding the lack thereof, the Pitch Rate Estimated is way overshooting the Setpoint so for the same throttle settings, FW_PR_FF needs to be drastically reduced to get closer to Setpoint, right?

Thank you for the insight.

4

That is probably the place to start. You may also need to adjust the other inner loop gains.