Vtol with single prop
Follow up work from this post , we decided to go for another flight to get a better tuned pitch controller, rectify airspeed sensor problems and collect more flight data before we push for TECS tuning.
A few hypotheses that we have been thinking about:
- Vibrations from the DLE61 gas engine got to the Cube’s pitch estimation, causing the dive
- Looking at the attitude graphs, the system knew that pitch was going down. It was also desiring more and more pitch as the aircraft dove downwards.
- error_RP data from NKF4 seem to indicate small errors.
- Plane pitch controllers (set of PIDP data) also seem to indicate that PID loops are actively kicking in to bring aircraft back to level
- One thing we did notice is that there was a lot of clipping of accelerometers while aircraft is still on the ground. However, the clipping events stopped when aircraft is in the air.
- Given that we were able to do a QLOITER with an engine in idle @ 2700 RPM, we aren’t sure if sensors and estimation are the cause of the problem.
| Type | Details | Type | Details |
|---|---|---|---|
| frame | FC | ||
| motor | ESC | ||
| RC | mode | ||
| weight | class | ||
| battery | air-time | ||
| configurator | last updated | ||
| airframe |
- GPS came loose and fell off right after transition is done
- No abrupt changes to magnetic heading and GPS lock status.
- No abrupt changes to magnetic heading and GPS lock status.
- Servo system failed & servo linkage arm broke in flight, right after transition is done.
- Post crash hardware tests seem to indicate otherwise. Because it was a nose dive, most of the rear of the aircraft was salvaged and test was possible.
- Post crash mechanical checks indicated that linkage arm and servo horn was still attached.
- Vibration matched resonance frequency of some component within the Cube, causing the Cube to send wrong signal out to MAIN2.
- We are not sure how to verify this
- We are not sure how to verify this
- Auto trimming of servo acted in the wrong way, coupled with effects of bad vibration on pitch estimation , causing elevator to compensate in the wrong direction.
- We are also not sure how to verify this
- We are also not sure how to verify this
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Products for this failed flight are as follows
- Dataflash logs
- Tlogs - if replaying, start from 99%
- Parameter file
- SummarySlidespdf or download pptx - we did up a slide deck to try summarize what we think to be key graphs and make sense of what’s going on
Products for previous successful flight
- Dataflash logs
- Tlogs
- Parameter file
- More details on this flight in this postA few hypotheses that we have been thinking about:
/****************/
Products for this failed flight are as follows
- Dataflash logs
- Tlogs - if replaying, start from 99%
- Parameter file
- Summary Slides - we did up a slide deck to try summarize what we think to be key graphs and make sense of what’s going on
- Flight video from ground view
- Post crash photo
- FFT chart
Products for previous successful flight
- Dataflash logs
- Tlogs
- Parameter file
- More details on this flight in this post Preview