I have a T-Drones M690Pro. Using a Cube Orange with Here 3+.
I’m using arducopter parameters supplied by the manufacturer for the model (with some changes to suit my telemetry hardware etc); but not tested or tuned on my particular drone. On the first flight it appeared to be flying okay (loiter mode with gentle inputs). But then while hovering in one spot it pitched forward abruptly, it was fairly windy/gusty but the pitching seemed excessive. I over-reacted and landed it abruptly which caused it to tip forward and shatter two props, otherwise okay. Phew.
I want to learn what I can from the logs before I decide how to proceed. I am contemplating starting from scratch with the methodic configurator (seems to be the standard response here), but am a little reluctant given I have parameters from the manufacturer; and maybe it was flying okay and it was just nervous operator error (i have not flown something this large before). Also I would really like to better understand the logs and diagnostics first. So I’m hoping someone can confirm my thoughts or make other suggestions, log file is here: 00000009.BIN - Google Drive and params here: Preflightparamcheck.param (18.9 KB).
My understanding so far is:
The VIBE.VIBEx parameters are averaging around 8, which is good.
While taking off / ascending (13:21:42-13:21:47) RCOU.Cx parameters indicate an appropriate level of thrust (around 1400) and are similar magnitude at this point so the motors are well aligned and the COG is fine.
After reaching altitude, the RCOU.Cx parameters fluctuate a lot for what was commanded (and which appeared) as relatively slow movement. As I understand it this indicates the PID values are poor and will result in unstable flight and motor overheating.
The RATE.ROUT and RATE.POUT parameters seem excessively noisy and high (I’ve read they should remain less than 0.1 and show less variance than in my example).
Are these conclusions appropriate or have I misunderstood something? I really want to understand this thoroughly so I can routinely monitor AP performance in future as I will be using this drone a lot.
Given these issues, it seems I should start from scratch (well step #7 in the methodic configurator guide) rather than try and fix the issue with the provided parameters. Or what are your thoughts?
Lastly, is anyone willing to share a log file from a well configured drone so I can see what things should look like? I can find lots of examples of logs with errors but no examples of things working well.
The parameter sets on the configurator are working well, and that is the reason we advise people to use it. It’s a collection of well configured parameters.
It also explains why the parameters get changed the way they are. That is the point of the “reason changed” informational field on every parameter.
So using the software will allow you to learn a lot, and for every single parameter it will show you the manufacturer parameters (current value) side-by-side with the recommended parameter value (new value).
If you want to preserve the manufacturer value, just change the new value to the current value or uncheck the upload tick-box.
If you want to use the new value recommended by the configurator, don’t change anything.
You are making this a bigger problem then it is, just use the configurator.
The workflow described above will meet ALL your needs.
Taking your advice I have been slowly and carefully working through the configurator from step 1. I am up to the first test flight.
I have used diff to compare all the parameters I flew with and those produced by the configurator, the parameters are very similar – which is not surprising as I had followed all those steps anyway. The one exception are the temperature calibration parameters (which are now set), but at the IMU temps experienced during the flight, the calibration didn’t have much of an impact, so I don’t think that will change much. The one thing I skipped is the motor thrust calibration, my motors are integrated in the drone, so even if I had a test stand I wouldn’t be able to use it (but I could build a test platform for the whole drone with load cells…). So I’m inclined to use the manufacturer values unless you think is a critical oversight.
So I’m still faced with the dilemma of not understanding the diagnostics from the first flight and being concerned about trying again with similar parameters.What I note from the configurator manual for flight one, is it states:
“Immediately check for hot motors. If the motors are too hot, check the .bin dataflash log, high or oscillating RATE.*out values indicate which PID gain you should reduce to remove the output oscillations causing the motors to heat up.”
Whilst I didn’t check if the motors were hot, the Rate.rout and rate.pout values concerned me. Where the configurator states “RATE.*out values indicate which PID gain you should reduce” I’m unclear which ones I should reduce and by how much.
Any advice would be appreciated.
Thanks!
Note: edited to remove a couple of questions I now have answers to.
I’ve plucked up the courage to try the first configurator flight and will report back. I’ve tweaked the PID values and will be flying with a 1kg dummy payload. That’s about the same as the real payloads I will be using and will address a really low hover throttle (AC reduced it to ~0.2 during the flight) which I think might have been part of the problem.
I spent the day flying today (working through the configurator) and it’s now working well. Reviewing the changes I think it was the reduction in PSC_ACC_Z_I and PSC_ACCZ_P that made the biggest difference. Having the IMU temperature calibrated and the notch filter properly setup will no doubt add to the robustness of the system!
I still haven’t done the final auto tune as the wind picked up, but it flies very responsively and smoothly. Thanks for pointing me at the configurator.
Once you are done, please post a .zip file with all the files created by the configurator and give me permission t publish them as a template in the software.
That will help future users.
The software automatically creates a .zip file once you reach the end.
